Hybrid illumination system with improved color quality
View Patent ↗A white light hybrid illumination system including an amber LED, a red LED, and a phosphor converted LED such as a blue LED chip and a green phosphor, wherein a peak emission difference between the amber and red LED is at least 25 nm. This system provides higher color quality than prior devices due to its high luminous efficacy, high CRI over a wide CCT range, and better color control.
1. A white light emitting device comprised of a first LED having a peak emission in the range 400 to 480 nm and a phosphor material radiationally coupled to said first LED, said phosphor material comprising a phosphor having a general formula of [(Sr 1−z M z ) 1(x+w) A w Ce x ] 3 (Al 1−y Si y )O 4+y+3(x−w) X 1−y−3(x−w) , wherein 0<x≦0.10 and 0≦y≦0.5, 0≦z≦0.5, 0≦w≦x, A is Li, Na, K, Rb, or any combinations thereof, M is Ca, Ba, Mg, Zn, or any combinations thereof, and X is a monovalent anion; a second LED having a peak emission in the range >615; and a third LED having a peak emission in the range of 580 to less than 610 nm and wherein said second LED has a peak emission between 35 and 40 nm greater than said third LED.
2. The white light emitting device of claim 1 wherein:
0<x≦0.05, 0.2≦y≦0.5, 0.2≦z≦0.5, A is Li, Na, or any combinations thereof, M is Ca, and X is F.
3. The white light emitting device of claim 1 wherein: 0.0025<x≦0.02, 0.3≦y≦0.5, 0.3≦z≦0.5.
4. The white light emitting device of claim 1 , wherein the combined light from the first LED will have a region in color space on the CIE 1931 chromaticity diagram bounded by the points having the color coordinates: x=0.171 and y=0.005; x=0.373 and y=0.624; x=0.039 and y=0.812; and x=0.124 and y=0.058.
5. The light emitting device of claim 1 , wherein said first LED is a violet to UV emitting LED with a peak emission wavelength between about 400 and 480 nm, and wherein said phosphor material comprises a green emitting phosphor capable of absorbing at least a portion of the radiation emitted from said first LED and emitting light having a peak wavelength in the range of from about 480 to 560 nm.
6. The light emitting device of claim 1 , wherein said second LED has a peak emission in the range of about 620 to 640 nm.
7. The light emitting device of claim 1 , wherein said third LED has a peak emission in the range of 580 to 600 nm.
8. The light emitting device of claim 1 , wherein said device has a CRI of at least 80.
9. The light emitting device of claim 1 , wherein said device has a CRI of at least 90.
10. The light emitting device of claim 1 , wherein said device has a luminous efficacy of greater than 330 Im/Wrad.
11. The light emitting device of claim 1 , wherein said device has a luminous efficacy of greater than 350 Im/Wrad.