Light emitting device with improved warm-white color point
A light emitting device is disclosed and includes an emission source configured to emit a primary blue light and a wavelength-converting element configured to convert the primary blue light to a secondary light, where the wavelength-converting element including a red phosphor material having a peak emission wavelength that is less than 620 nm and a green phosphor material having a peak emission wavelength that is greater than 530 nm. The device may have a correlated color temperature (CCT) in the range of 1600K-2500K, may exhibit a melanopic/photopic ratio less than 0.25 and/or may exhibit a radiometric power fraction of light having a wavelength below 530 nm below 0.1.
1. A light emitting device, comprising:
an emission source configured to emit a primary blue light; and
a wavelength-converting element comprising a red phosphor material having a peak emission wavelength that is less than 620 nm and a green phosphor material having a peak emission wavelength that is greater than 530 nm, the wavelength-converting element configured to convert the primary blue light to a secondary light;
the light emitting device configured to emit a white light comprising the primary blue light and the secondary light, the white light having a correlated color temperature (CCT) between 1600K and 2500K and a melanopic/photopic ratio less than 0.25.
2. The light emitting device of claim 1 , wherein the red phosphor has a peak emission wavelength of approximately 604 nm, and the green phosphor has a peak emission wavelength of approximately 543 nm.
3. The light emitting device of claim 1 , wherein the emission source comprises at least one light emitting diode.
4. The light emitting device of claim 1 , wherein the peak emission wavelength of the green phosphor material is approximately in a range 530-560 nm and the peak emission wavelength of the red phosphor material is approximately in a range of 580-620 nm.
5. The light emitting device of claim 1 , wherein the wavelength-converting element has a green-to-red phosphor weight ratio of approximately 1.6.
6. The light emitting device of claim 1 , wherein the wavelength-converting element has a green-to-red phosphor weight ratio of approximately 1.01.
7. The light emitting device of claim 1 , wherein the wavelength-converting element has a green-to-red phosphor weight ratio of approximately 0.64.
8. The light emitting device of claim 1 , wherein the red phosphor material and the green phosphor material are suspended in a silicone matrix, and the wavelength-converting element has a phosphor-to-silicon mass ratio in the range of 0.62-0.68.
9. The light emitting device of claim 1 , wherein the white light has a color rendering index (CRI) in a range of 40-60.
10. A light emitting device, comprising:
an emission source configured to emit a primary blue light; and
a wavelength-converting element comprising a red phosphor material having a peak emission wavelength that is less than 620 nm and a green phosphor material having a peak emission wavelength that is greater than 530 nm, the wavelength-converting element configured to convert the primary blue light to a secondary light;
the light emitting device configured to emit a white light comprising the primary blue light and the secondary light, the white light having a correlated color temperature (CCT) between 1600K and 2500K and a radiometric power fraction of light having a wavelength below 530 nm below 0.1.
11. The light emitting device of claim 10 , wherein the red phosphor has a peak emission wavelength of approximately 604 nm, and the green phosphor has a peak emission wavelength of approximately 543 nm.
12. The light emitting device of claim 10 , wherein the emission source comprises at least one light emitting diode.
13. The light emitting device of claim 10 , wherein the peak emission wavelength of the green phosphor material is approximately in a range 530-560 nm and the peak emission wavelength of the red phosphor material is approximately in a range of 580-620 nm.
14. The light emitting device of claim 10 , wherein the wavelength-converting element has a green-to-red phosphor weight ratio of approximately 1.6.
15. The light emitting device of claim 10 , wherein the wavelength-converting element has a green-to-red phosphor weight ratio of approximately 1.01.
16. The light emitting device of claim 10 , wherein the wavelength-converting element has a green-to-red phosphor weight ratio of approximately 0.64.
17. The light emitting device of claim 10 , wherein the secondary light has a color rendering index (CRI) in a range of 40-60.
18. The light emitting device of claim 10 , wherein the red phosphor material and the green phosphor material are suspended in a silicone matrix, and the wavelength-converting element has a phosphor-to-silicon mass ratio in the range of 0.62-0.68.
19. The light emitting device of claim 10 , wherein the red phosphor material comprises a BSSNE phosphor.
20. The light emitting device of claim 10 , wherein the green phosphor material comprises a YAG phosphor.