Filters for circadian lighting
View Patent ↗A light source comprising: (a) An LED source comprising at least one LED emitting an LED emission and at least one wavelength-converting material configured to convert a fraction of the LED emission, the LED source emitting a primary SPD; and (b) at least one optical element configured to interact with the primary SPD to remove radiation in the primary SPD, such that a final SPD is emitted from the light source; wherein a fraction of the primary SPD in the wavelength range 430-500 nm is less than 5%; and a fraction of the final SPD in the wavelength range 430-500 nm is less than 1%.
1. A light source comprising:
at least one LED having at least one emitter of blue or violet light and a plurality of wavelength converting materials configured to convert at least a portion of said blue or violet light to converted emissions having different wavelengths, wherein said LED emits an unfiltered emission of white light having an unfiltered chromaticity;
at least one notch filter configured to receive at least a portion of said unfiltered emission and having a transmission configuration to reduce circadian stimulation by removing a portion of said blue or violet light from said unfiltered emission to emit a final emission, said filtered emission having a filtered spectral power distribution (SPD) with a filtered power in the range 380-780 nm and with a blue fraction power in the range 430-500 nm, wherein said blue power fraction is less than 1% of said filtered power, and said filtered emission having a filtered chromaticity with a distance to the Planckian locus Du′v′ of less than 0.01;
wherein an emission spectrum of said phosphor and said transmission configuration of said notch filter are jointly configured to result in a small a Du′v′ distance between said pre-filtered chromaticity and said filtered chromaticity of less than 0.007.
2. The light source of claim 1 , wherein said first wavelength corresponds to violet.
3. The light source of claim 2 , wherein said filtered SPD has a violet fraction filtered power in the range 400-430 nm, of at least 5% of said filtered SPD.
4. The light source of claim 3 , wherein the ratio of blue fraction filtered power to violet fraction filtered power is less than 0.1.
5. The light source of claim 1 , wherein said filtered emission has a color rendering index greater than 80.
6. A light source comprising:
an LED having at least one emitter of blue or violet light and at least one phosphor, and being configured for emitting an unfiltered emission of white light said unfiltered emission having a unfiltered chromaticity and an unfiltered SPD with an unfiltered power in the range of 380-780 nm and with a blue fraction unfiltered power in the range of 430-500 nm, said blue fraction unfiltered power is less than 5% of said unfiltered power; and
at least one optical element, including a notch filter to reduce circadian stimulation by removing a portion of said blue or violet light from said unfiltered emission, said at least one optical element being optically coupled to said LED source and configured to receive at least a portion of said unfiltered emission, said at least one optical element having a transmission configuration to remove radiation in the range of 430-500 nm from said unfiltered emission, resulting in a final emission having a final chromaticity and a final SPD with a final power in the range of 380-780 nm and a blue fraction final power in the range of 430-500 nm, said blue fraction final power being significantly reduced from said blue fraction unfiltered power such that said blue fraction final power is less than 1% of said final power, wherein an emission spectrum of said phosphor and said transmission configuration of said notch filter are jointly configured to result in a small Du′v′ distance between said unfiltered chromaticity and said final chromaticity of less than 0.007.
7. The light source of claim 6 , wherein said filtered SPD has a violet fraction filtered power in the range 400-430 nm of at least 5% of said filtered SPD.
8. The light source of claim 7 , wherein the ratio of blue fraction filtered power to violet fraction filtered power is less than 0.1.
9. The light source of claim 6 , wherein the final chromaticity has a distance to the Planckian locus Du′v′ less than 0.01.
10. The light source of claim 6 , wherein said blue fraction final power is less than 0.5% of said final.
11. The light source of claim 6 , wherein a color rendering index Ra of the final emission is higher than 80.
12. The light source of claim 6 , wherein the optical element is a filter.
13. The light source of claim 6 , wherein the CCT of the unfiltered emission is in the range 2600-3500K.
14. The light source of claim 6 , wherein the CCT of the filtered emission is in the range 2600-3500K.