Semiconductor light emitting devices having selectable and/or adjustable color points and related methods
First Claim
1. A method for fabricating a semiconductor light emitting device, the method comprising:
- providing a first string of light emitting diodes (“
LED”
) that comprises a first LED that has a first recipient luminophoric medium that comprises a first luminescent material that emits light comprising a peak wavelength within the green color range in response to radiation emitted by the first LED;
providing a second string of LEDs that comprises a second LED that has a second recipient luminophoric medium that comprises a second luminescent material that emits light comprising a peak wavelength within the yellow color range in response to radiation emitted by the second LED;
providing a third string of LEDs that comprises a third LED that emits light comprising a distinct spectral peak within the red color range or the orange color range;
selecting the LEDs included in the first string and in the second string so that when the first string and second string are operated at pre-selected drive current levels the combined light output of the first string and the second string is on a line on the 1931 CIE Chromaticity Diagram that is defined by the color point for the combined output of the third sting and a pre-selected color point for the light output by the semiconductor light emitting device.
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Accused Products
Abstract
Semiconductor light emitting devices are provided that include a first string of light emitting diodes (“LED”) that emit unsaturated light having a color point that is within at least eight MacAdam ellipses of one or more points within a first blue-shifted-yellow region on the 1931 CIE Chromaticity Diagram, a second string of LEDs that emit unsaturated light having color point that is within at least eight MacAdam ellipses from one or more points within a second blue-shifted-green region on the 1931 CIE Chromaticity Diagram, and a third light source that emits radiation having a dominant wavelength between 600 and 720 nm. A drive circuit is provided that is configured to supply a first drive current to the first string of LEDs, a second drive current to the second string of LEDs and a third drive current to the third string of LEDs, wherein at least two of the first, second and third drive currents are independently controllable.
52 Citations
22 Claims
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1. A method for fabricating a semiconductor light emitting device, the method comprising:
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providing a first string of light emitting diodes (“
LED”
) that comprises a first LED that has a first recipient luminophoric medium that comprises a first luminescent material that emits light comprising a peak wavelength within the green color range in response to radiation emitted by the first LED;providing a second string of LEDs that comprises a second LED that has a second recipient luminophoric medium that comprises a second luminescent material that emits light comprising a peak wavelength within the yellow color range in response to radiation emitted by the second LED; providing a third string of LEDs that comprises a third LED that emits light comprising a distinct spectral peak within the red color range or the orange color range; selecting the LEDs included in the first string and in the second string so that when the first string and second string are operated at pre-selected drive current levels the combined light output of the first string and the second string is on a line on the 1931 CIE Chromaticity Diagram that is defined by the color point for the combined output of the third sting and a pre-selected color point for the light output by the semiconductor light emitting device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A semiconductor light emitting device, comprising:
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a first light emitting diode (“
LED”
) string that comprises a first LED that has a first recipient luminophoric medium that comprises a first luminescent material that emits light comprising a peak wavelength within the green color range in response to radiation emitted by the first LED;a second LED string that comprises a second LED that has a second recipient luminophoric medium that comprises a second luminescent material that emits light comprising a peak wavelength within the yellow color range in response to radiation emitted by the second LED; a third LED string that comprises a third LED that emits light comprising a distinct spectral peak within the red color range or the orange color range; and a drive circuit that is responsive to input from an end user of the semiconductor light emitting device, the drive circuit configured to adjust the relative values of the drive currents provided to the LEDs in the first and second LED strings to adjust a color point of the light emitted by the semiconductor light emitting device. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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19. A semiconductor light emitting device, comprising:
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a first light emitting diode (“
LED”
) string that comprises a first LED that has a first recipient luminophoric medium that comprises a first luminescent material that emits light comprising a peak wavelength within the green color range in response to radiation emitted by the first LED;a second LED string that comprises a second LED that has a second recipient luminophoric medium that comprises a second luminescent material that emits light comprising a peak wavelength within the yellow color range in response to radiation emitted by the second LED; a third LED string that comprises a third LED that emits light comprising a distinct spectral peak within the red color range or the orange color range; and a multi-position switch comprising a plurality of settings that correspond to a plurality of different pre-selected drive current values for driving the respective first, second and third LED strings to provide light comprising pre-selected color points. - View Dependent Claims (20, 21, 22)
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Specification