Phosphor systems for a white light emitting diode (LED)
First Claim
1. A white LED comprising:
- a radiation source configured to emit radiation having a wavelength ranging from about 250 to 420 nm;
a yellow phosphor configured to absorb at least a portion of the radiation from the radiation source and emit light with peak intensity in a wavelength ranging from about 530 to 590 nm, wherein the yellow phosphor has the formula A2SiO4;
Eu2+F and A is at least one of a divalent metal selected from the group consisting of Sr, Ca, Ba, Mg, Zn, and Cd, and wherein the fluorine dopant substitutes for oxygen; and
a blue phosphor configured to absorb at least a portion of the radiation from the radiation source and emit light with peak intensity in a wavelength ranging from about 470 to 530 nm.
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Accused Products
Abstract
Novel phosphor systems for a white LED are disclosed. The phosphor systems are excited by a non-visible to near-UV radiation source having an excitation wavelength ranging from about 250 to 420 nm. The phosphor system may comprise one phosphor, two phosphors, and may include optionally a third and even a fourth phosphor. In one embodiment of the present invention, the phosphor is a two phosphor system having a blue phosphor and a yellow phosphor, wherein the long wavelength end of the blue phosphor is substantially the same wavelength as the short wavelength end of the yellow phosphor. Alternatively, there may be a wavelength gap between the yellow and blue phosphors. The yellow phosphor may be phosphate or silicate-based, and the blue phosphor may be silicate or aluminate-based. Single phosphor systems excited by non-visible radiation are also disclosed. In other embodiments of present invention, a single phosphor is used to produce white light illumination, the single phosphor having a broad emission spectrum with a peak intensity ranging from about 520 to 560 nm.
74 Citations
27 Claims
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1. A white LED comprising:
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a radiation source configured to emit radiation having a wavelength ranging from about 250 to 420 nm; a yellow phosphor configured to absorb at least a portion of the radiation from the radiation source and emit light with peak intensity in a wavelength ranging from about 530 to 590 nm, wherein the yellow phosphor has the formula A2SiO4;
Eu2+F and A is at least one of a divalent metal selected from the group consisting of Sr, Ca, Ba, Mg, Zn, and Cd, and wherein the fluorine dopant substitutes for oxygen; anda blue phosphor configured to absorb at least a portion of the radiation from the radiation source and emit light with peak intensity in a wavelength ranging from about 470 to 530 nm. - View Dependent Claims (2, 3, 4, 5, 6, 8, 9, 10, 11)
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7. A white LED comprising:
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a radiation source configured to emit radiation having a wavelength ranging from about 250 to 420 nm; a yellow phosphor configured to absorb at least a portion of the radiation from the radiation source and emit light with peak intensity in a wavelength ranging from about 530 to 590 nm; and a blue phosphor configured to absorb at least a portion of the radiation from the radiation source and emit light with peak intensity in a wavelength ranging from about 470 to 530 nm; wherein the yellow phosphor has the formula (Sr1-x-yEuxMny)2P2+zO7; and
where0.03≦
x≦
0.08;0.06≦
y≦
0.16; and0<
z≦
0.05.
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12. A white LED comprising:
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a radiation source configured to emit radiation having a wavelength ranging from about 250 to 420 nm; a yellow phosphor configured to absorb at least a portion of the radiation from the radiation source and emit light with a peak intensity in a wavelength ranging from about 550 to 590 nm;
wherein the yellow phosphor has the formula A2SiO4;
Eu2+F and A is at least one of a divalent metal selected from the group consisting of Sr, Ca, Ba, Mg, Zn, and Cd, and wherein the fluorine dopant substitutes for oxygen anda blue phosphor configured to absorb at least a portion of the radiation from the radiation source and emit light with a peak intensity in a wavelength ranging from about 480 to 510 nm. - View Dependent Claims (13, 14, 15, 16, 17, 19, 20, 21, 22)
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18. A white LED comprising:
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a radiation source configured to emit radiation having a wavelength ranging from about 250 to 420 nm; a yellow phosphor configured to absorb at least a portion of the radiation from the radiation source and emit light with peak intensity in a wavelength ranging from about 530 to 590 nm; and a blue phosphor configured to absorb at least a portion of the radiation from the radiation source and emit light with peak intensity in a wavelength ranging from about 470 to 530 nm; wherein the yellow phosphor has the formula (S1-x-yEuxMny)2P2+zO7; and
where0.03≦
x≦
0.08;0.06≦
y≦
0.16; and0<
z≦
0.05.
-
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23. A white LED having a single phosphor system, the phosphor system comprising:
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a radiation source configured to emit radiation having a wavelength ranging from about 250 to 420 nm; and a phosphor configured to absorb at least a portion of the radiation from the radiation source and emit a broad spectrum light with a peak intensity in a wavelength ranging from about 520 to 560 nm, wherein the yellow phosphor has the formula A2SiO4;
Eu2+F and A is at least one of a divalent metal selected from the group consisting of Sr, Ca, Ba, Mg, Zn, and Cd, and wherein the fluorine dopant substitutes for oxygen. - View Dependent Claims (24, 25, 26)
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27. A method of producing white light illumination from a two-phosphor system, the method comprising:
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providing a radiation source configured to emit radiation having a wavelength ranging from about 250 to 420 nm; exposing a yellow phosphor to at least a portion of the radiation from the radiation source to produce light having a wavelength ranging from about 530 to 590 nm; exposing a blue phosphor to at least a portion of the radiation from the radiation source to produce light having a wavelength ranging from about 470 to 530 nm; and mixing the light from the yellow phosphor with the light from the blue phosphor to produce the white illumination.
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Specification