Circadian-friendly LED light source
Methods and apparatus for providing circadian-friendly LED light sources are disclosed. A light source is formed to include a first LED emission (e.g., one or more LEDs emitting a first spectrum) and a second LED emission (e.g., one or more LEDs emitting a second spectrum) wherein the first and second LED emissions are combined in a first ratio and in a second ratio such that while changing from the first ratio to the second ratio the relative circadian stimulation is varied while maintaining a color rendering index above 80.
1. A light emitter comprising:
one or more LEDs configured to emit LED light, said one or more LEDs comprising at least a violet LED configured to emit a light with a peak wavelength of 405-435 nm;
at least one phosphor configured to emit converted light by converting a fraction of said LED light; and
wherein said light emitter emits an emitted light comprising at least a combination of a fraction of said LED light and said converted light, said emitted light having a spectral power distribution (SPD), said SPD having a first power from 350 nm to 850 nm and a second power from 400 nm to about 440 nm, and a third power from about 440 to about 500 nm, wherein said second power is at least 10% of said first power, wherein the ratio said second power to said third power is at least 1 and no greater than 5, and wherein said SPD has a CRI greater than 80 and an R9 greater than 0.
2. The light emitter of claim 1 , wherein at least a portion light emitted from said violet LED pumps said at least one phosphor.
3. The light emitter of claim 1 , wherein one or more LEDs comprises a second LED configured to emit a second light, wherein said one or more LEDs are configured to emit at least a first LED light and a second LED light by varying the amount of said at least one violet LED and said at least one second LED in said LED light.
4. The light emitter of claim 3 , wherein said second LED comprises a blue LED.
5. The light emitter of claim 4 , wherein at least a portion light emitted from said blue LED pumps said at least one phosphor.
6. The light emitter of claim 4 , wherein said blue LED has a peak wavelength of 470 nm.
7. The light emitter of claim 1 , wherein said second power is at least one of at least 25%, at least 20%, or at least 15%.
8. A light source for emitting emitted light, said light source comprising:
a first channel for emitting a low circadian stimulation (CS) light, said first channel comprising a violet LED for emitting violet light having a peak wavelength of 405-435 nm, and at least one wavelength converting material for converting a portion of said violet light to a first converted light, wherein said low CS light comprises a combination of said violet light and said first converted light, said low CS light having a first spectral power distribution (SPD) from 350 to 850 nm and fractions Fv1 and Fc1, Fv1 representing a fraction of power of said first SPD in the wavelength range from 400 nm to 440 nm, and Fc1 representing a fraction of power of said first SPD in the wavelength range from 440 nm to 500 nm;
a second channel for emitting a high CS light, said second channel comprising a blue LED for emitting blue light having a peak wavelength of 440-500 nm, and at least one wavelength converting material for converting a portion of said blue light to a second converted light, wherein said high CS light comprises a combination of said blue light and said second converted light, said high CS light having a second SPD from 350 to 850 nm and fractions Fv2 and Fc2, Fv2 representing a fraction of power of said second SPD in the wavelength range from 400 nm to 440 nm, and Fc2 representing a fraction of power of said second SPD in the wavelength range from 440 nm to 500 nm; and
circuitry for driving said first and second channels independently such that said emitted light is at least one of said low CS light, said high CS light, or a combination of said low CS light and said high CS light.
9. The light source of claim 8 , wherein said violet light has a peak wavelength of 405-430 nm.
10. The light source of claim 9 , wherein said violet light has a peak wavelength of 425 nm.
11. The light source of claim 8 , wherein said blue light has a peak wavelength of 440-470 nm.
12. The light source of claim 11 , wherein said blue light has a peak wavelength of 470 nm.
13. The light source of claim 8 , wherein CS of said high CS light is more than 2 times that of said low CS light.
14. The light source of claim 8 , wherein CS of said high CS light is more than 3 times that of said low CS light.
15. The light source of claim 8 , wherein Fc1 is less than 0.05 and Fc2 is at least 0.1.
16. The light source of claim 8 , wherein Fc1 is less than 0.01.
17. The light source of claim 8 , wherein Fv1 is at least 0.05.
18. The light source of claim 8 , wherein Fv1 is at least 0.2.
19. The light source of claim 8 , wherein said first and second channels are contained in separate packages.
20. The light source of claim 8 , wherein said circuitry is configured to adjust the ratio of said low CS light and said high CS light without changing CCT or chromaticity of said emitted light.
21. The light source of claim 8 , further comprising a third channel having a third LED different from said violet LED and said blue LED.
22. The light source of claim 8 , further comprising at least one control circuit configured to learn from user behavior to regulate said emitted light between said low CS light and said high CS light.