Semiconductor light emitting devices having selectable and/or adjustable color points and related methods
First Claim
Patent Images
1. A light emitting device, comprising:
- a first string of at least one light emitting diode (“
LED”
);
a second string of at least one LED;
a third string of at least one LED;
a drive circuit that is configured to set the relative drive currents provided to the first string and to the second string so that the color point on the 1931 CIE Chromaticity Diagram of the combined output of the first string and the second string is approximately on a line that extends on the 1931 CIE Chromaticity Diagram through a pre-selected color point and a color point of an output of the third string, and that is further configured to set the relative drive currents provided to the third string relative to the drive currents provided to the first and second strings so that the color point on the 1931 CIE Chromaticity Diagram of the combined output of the light emitting device is approximately at the pre-selected color pointwherein one of the first through third strings includes at least one blue-shifted-yellow LED, and wherein one of the first through third strings of LEDs includes at least one blue-shifted-green LED.
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Abstract
Semiconductor light emitting devices include a first string of at least one blue-shifted-yellow LED, a second string of at least one blue-shifted-green LED, and a third string of at least one LED that emits light in the red color range. These devices include at least a first circuit that is configured to provide an operating current to at least one of the first LED or the second LED and a second circuit that is configured to provide an operating current to the third light source. The drive currents supplied by the first and second circuits may be independently controlled to set a color point of the light emitting device at a desired color point.
57 Citations
23 Claims
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1. A light emitting device, comprising:
-
a first string of at least one light emitting diode (“
LED”
);a second string of at least one LED; a third string of at least one LED; a drive circuit that is configured to set the relative drive currents provided to the first string and to the second string so that the color point on the 1931 CIE Chromaticity Diagram of the combined output of the first string and the second string is approximately on a line that extends on the 1931 CIE Chromaticity Diagram through a pre-selected color point and a color point of an output of the third string, and that is further configured to set the relative drive currents provided to the third string relative to the drive currents provided to the first and second strings so that the color point on the 1931 CIE Chromaticity Diagram of the combined output of the light emitting device is approximately at the pre-selected color point wherein one of the first through third strings includes at least one blue-shifted-yellow LED, and wherein one of the first through third strings of LEDs includes at least one blue-shifted-green LED. - View Dependent Claims (2, 3, 4)
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5. A method of tuning a multi-emitter semiconductor light emitting device to a desired color point, the method comprising:
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setting the relative drive currents provided to a first string of at least one light emitting diode (“
LED”
) and to a second string of at least one LED so that the color point on the 1931 CIE Chromaticity Diagram of the combined output of the first string and the second string is approximately on a line that extends on the 1931 CIE Chromaticity Diagram through the desired color point and a color point of a combined output of a third string of at least one LED; andsetting a drive current provided to the third string of at least one LED so that the color point on the 1931 CIE Chromaticity Diagram of the combined output of the multi-emitter semiconductor light emitting device is approximately at the desired color point wherein one of the first through third strings of LEDs includes at least one blue-shifted-yellow LED, and wherein one of the first through third strings of LEDs includes at least one blue-shifted-green LED. - View Dependent Claims (6, 7, 8)
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9. A semiconductor light emitting device, comprising:
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a first light emitting diode (“
LED”
) that emits radiation having a peak wavelength between 400 and 490 nm that includes a first recipient luminophoric medium, wherein a color point of the combined light output of the first LED and the first recipient luminophoric medium falls within the region on the 1931 CIE Chromaticity Diagram defined by x, y chromaticity coordinates (0.32, 0.40), (0.36, 0.48), (0.43 0.45), (0.36, 0.38), (0.32, 0.40);a second LED that emits radiation having a peak wavelength between 400 and 490 nm that includes a second recipient luminophoric medium, wherein a color point of the combined light output of the second LED and the second recipient luminophoric medium falls within the region on the 1931 CIE Chromaticity Diagram defined by x, y chromaticity coordinates (0.35, 0.48), (0,26, 0.50), (0.13 0.26), (0.15, 0.20), (0.26, 0.28), (0.35, 0.48); a third light source that emits radiation having a dominant wavelength between 600 and 720 nm; a first circuit that is configured to provide an operating current to at least one of the first LED or the second LED; and an independently controllable second circuit that configured to provide an operating current to the third light source. - View Dependent Claims (10, 11, 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 includes at least one first type of LED;a second LED string that includes at least one second type of LED; a third LED string that includes at least one third type of LED; a circuit that allows an end user of the semiconductor light emitting device to adjust the relative values of the drive current 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 (20, 21, 22, 23)
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Specification