White LEDs with tailorable color temperature
First Claim
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1. A lighting apparatus for emitting white light comprising:
- a semiconductor light source emitting radiation having a peak emission in the range of from about 250 to 500 nm;
a first phosphor material comprising at least one phosphor composition radiationally coupled to said light source; and
a second phosphor material comprising at least one phosphor composition radiationally coupled to said light source;
wherein the first and second phosphor materials have emissions with different x, y color coordinates on the 1931 CIE chromaticity diagram when subjected to the same source excitation radiation, with the emissions from the first and second phosphor materials lying substantially on the black body locus, taken either alone or with residual light bleed from the semiconductor light source.
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Abstract
A method for the manufacturing of white LEDs is proposed, which can achieve a tunable CCT through the use of at least two phosphor materials, each composition including at least one individual phosphor compound. The method allows optimization of the devices for any desired CCT and approximation of the color coordinates of the black body (Planckian) locus.
123 Citations
24 Claims
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1. A lighting apparatus for emitting white light comprising:
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a semiconductor light source emitting radiation having a peak emission in the range of from about 250 to 500 nm;
a first phosphor material comprising at least one phosphor composition radiationally coupled to said light source; and
a second phosphor material comprising at least one phosphor composition radiationally coupled to said light source;
wherein the first and second phosphor materials have emissions with different x, y color coordinates on the 1931 CIE chromaticity diagram when subjected to the same source excitation radiation, with the emissions from the first and second phosphor materials lying substantially on the black body locus, taken either alone or with residual light bleed from the semiconductor light source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for making a lighting apparatus for emitting white light which can achieve a tunable CCT by varying the amounts of first and second phosphor materials present in said apparatus, the method including the steps of
providing a semiconductor light source emitting radiation having a peak emission at from about 250 to 500 nm; -
providing a first phosphor material comprising at least one phosphor composition radiationally coupled to said light source; and
providing a second phosphor material comprising at least one phosphor composition radiationally coupled to said light source;
wherein the first and second phosphor materials have emissions with different x, y color coordinates on the 1931 CIE chromaticity diagram when subjected to the same source excitation radiation, with the emissions from the first and second phosphor materials lying substantially on the black body locus, taken either alone or with residual light bleed from the semiconductor light source. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A white light illumination system comprising a radiation source and first and second phosphor materials, wherein:
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an emission spectrum of the first phosphor material represents a first point on a CIE chromaticity diagram;
an emission spectrum of the second phosphor material represents a second point on the CIE chromaticity diagram;
the emissions from the first and second phosphor materials lie substantially on the black body locus, taken either alone or with residual light bleed from the radiation source;
a first line connecting the first point and the second point lies substantially on the black body locus; and
radiation emitted by the system lies substantially on the black body locus.
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Specification