White light illumination system with improved color output
AssigneeGeneral Electric Company
InventorsAnil Raj Duggal, Alok Mani Srivastava, Holly Ann Comanzo
Life of this patent
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Abstract
There is provided a white light illumination system including a blue LED and a luminescent material. The system color output is improved when a line connecting the LED color coordinates and the luminescent material color coordinates approximates the Black Body Locus on the CIE chromatically diagram. The LED may have a peak emission wavelength between 470 and 500 nm. The luminescent material may be (Y1−x−zGdxCez)3Al5O12, where 0.7>x>0.4 and 0.1>z>0.
Claims61
A white light illumination system comprising a radiation source and a luminescent material, wherein:
- an emission spectrum of the radiation source represents a first point on a CIE chromaticity diagram;
- an emission spectrum of the luminescent material represents a second point on the CIE chromaticity diagram;
- a first line connecting the first point and the second point approximates a Black Body Locus on the CIE chromaticity diagram;
- and
- radiation emitted by the system approximates the Black Body Locus on the CIE chromaticity diagram substantially independent of a thickness of the luminescent material for color temperatures ranging from 4000 K to 6000 K.
A white light illumination system comprising:
- a) a luminescent material, comprising:
- (A1−xGdx)3D5E12:Ce,
- wherein A comprises at least one of Y, Lu, Sm and La;
- D comprises at least one of Al, Ga, Sc and In;
- E comprises oxygen;
- and
- x>0.4;
- b) a light emitting diode having a peak emission wavelength greater than 470 nm;
- and
- wherein radiation emitted by the system approximates a Black Body Locus on a CIE chromaticity diagram substantially independent of a thickness of the luminescent material for color temperatures ranging from 4000 K to 6000 K.
A method of making a white light illumination system containing a radiation source and a luminescent material, comprising:
- selecting a first line which approximates a Black Body Locus on a CIE chromaticity diagram;
- forming the radiation source, wherein an emission spectrum of the radiation source is represented by a first point on the first line;
- and
- forming the luminescent material, wherein an emission spectrum of the luminescent material is represented by a second point on the first line.
A method of making a white light illumination system containing a radiation source and a luminescent material, comprising:
- selecting the radiation source whose emission spectrum represents a first point on a CIE chromaticity diagram;
- selecting the luminescent material whose emission spectrum represents a second point on the CIE chromaticity diagram, such that a first line connecting the first point and the second point approximates a Black Body Locus on the CIE chromaticity diagram;
- and
- placing the radiation source and the luminescent material into the white light illumination system.
A white light illumination system comprising a radiation source and a luminescent material, wherein:
- an emission spectrum of the radiation source represents a first point on a CIE chromaticity diagram;
- the radiation source comprises a light emitting diode having a peak emission wavelength of 475 to 480 nm;
- an emission spectrum of the luminescent material represents a second point on the CIE chromaticity diagram;
- and
- a first line connecting the first point and the second point approximates a Black Body Locus on the CIE chromaticity diagram.
A white light illumination system comprising:
- a) a luminescent material, comprising:
- (A1−xGdx)3D5E12:Ce,
- wherein A comprises at least one of Y, Lu, Sm and La;
- D comprises at least one of Al, Ga, Sc and In;
- E comprises oxygen;
- and
- x>0.4;
- b) a light emitting diode having a peak emission wavelength of 475 to 480 nm.
Dependencies are inferred from the claim text.