High CRI white light emitting devices and drive circuitry
First Claim
1. A white light emitting device comprising:
- at least one blue solid state light emitter operable to generate blue light with a dominant wavelength in a range 400 nm to 480 nm;
at least one phosphor material operable to absorb a portion of the blue light and to emit light with a dominant wavelength in a range 490 nm to 590 nm; and
at least one red solid state light emitter operable to generate red light with a dominant wavelength in a range 600 nm to 700 nm, whereinan emission product of the white light emitting device comprises combined light generated by the blue and red light emitters and light generated by the at least one phosphor material and appears white in color; and
a drive circuit operable to compensate for variation in a ratio of red to blue light in the emission product such that over an operating temperature range of at least 25°
C., said variation is less than 20%.
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Accused Products
Abstract
A high CRI white light emitting device comprises: a blue solid state light emitter (LED) operable to generate blue light; a phosphor material operable to absorb a portion of the blue light and to emit green/yellow light and a red solid state light emitter (LED) operable to generate red light. The emission product of the device comprises the combined light generated by the blue and red LEDs and green/yellow light generated by the phosphor material and appears white in color. The device further comprises a drive circuit operable to compensate for variation in the ratio (relative contribution) of red to blue light in the emission product such as to ensure that said variation is less than 20% over an operating temperature range of at least 25° C. The drive circuit can reduce variation in the CRI and CCT of the device'"'"'s emission product over the operating temperature range.
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Citations
29 Claims
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1. A white light emitting device comprising:
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at least one blue solid state light emitter operable to generate blue light with a dominant wavelength in a range 400 nm to 480 nm; at least one phosphor material operable to absorb a portion of the blue light and to emit light with a dominant wavelength in a range 490 nm to 590 nm; and at least one red solid state light emitter operable to generate red light with a dominant wavelength in a range 600 nm to 700 nm, wherein an emission product of the white light emitting device comprises combined light generated by the blue and red light emitters and light generated by the at least one phosphor material and appears white in color; and a drive circuit operable to compensate for variation in a ratio of red to blue light in the emission product such that over an operating temperature range of at least 25°
C., said variation is less than 20%. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A white light emitting device comprising:
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at least one blue LED operable to generate blue light; at least one phosphor material operable to absorb a portion of the blue light and to emit green/yellow light; and at least one red LED operable to generate red light, wherein an emission product of the white light emitting device comprises combined light generated by the blue and red light LEDs and green/yellow light generated by the at least one phosphor material and appears white in color; and a drive circuit operable to compensate for variation in the ratio of red to blue light in the emission product such that over an operating temperature range of at least 25°
C., said variation is less than 20%.
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Specification