White light emitting phosphor blend for LED devices
View Patent ↗There is provided a white light illumination system including a radiation source, a first luminescent material having a peak emission wavelength of about 570 to about 620 nm, and a second luminescent material having a peak emission wavelength of about 480 to about 500 nm, which is different from the first luminescent material. The LED may be a UV LED and the luminescent materials may be a blend of two phosphors. The first phosphor may be an orange emitting Eu 2+ , Mn 2+ doped strontium pyrophosphate, (Sr 0.8 Eu 0.1 Mn 0.1 ) 2 P 2 O 7 . The second phosphor may be a blue-green emitting Eu 2+ doped SAE, (Sr 0.90-0.99 Eu 0.01-0.1 ) 4 Al 14 O 25 . A human observer perceives the combination of the orange and the blue-green phosphor emissions as white light.
1. A white light illumination system comprising:
a radiation source; and
a radiation-to-light converter consisting essentially of:
a first luminescent material having a peak emission wavelength of about 590 nm; and
a second luminescent material having a peak emission wavelength of about 480 to about 500 nm, which is different from the first luminescent material.
2. The system of claim 1 , wherein the white light emitted by the system lacks any significant visible component emitted by the radiation source, and the output of the first and second luminescent material appears as white light to a human observer.
3. The system of claim 2 , wherein the white light emitted by the system is substantially free of any component emitted by the radiation source having a wavelength in the range of about 420 nm to about 650 nm.
4. The system of claim 1 , wherein the radiation source peak emission wavelength is 360 to 420 nm.
5. The system of claim 4 , wherein the radiation source comprises a light emitting diode containing an InGaN active layer and having a peak emission wavelength between 370 and 405 nm.
6. The system of claim 1 , wherein: the radiation source comprises a gas contained in a fluorescent lamp; and a radiation emitted by the radiation source comprises ultraviolet radiation.
7. The system of claim 1 , wherein: the radiation source comprises a gas contained in a plasma display; and a radiation emitted by the radiation source comprises ultraviolet radiation.
8. A white light illumination system comprising:
a radiation source; and
a radiation-to-light conversion material which absorbs radiation from the radiation source and produces white light, consisting essentially of:
an orange light emitting phosphor; and
a blue-green light emitting phosphor.
9. The system as set forth in claim 8 , wherein the orange light emitting phosphor has a peak emission wavelength of about 570 to about 620 nm; and wherein the blue-green phosphor has a peak emission wavelength of about 480 to about 500 nm.
10. The system as set forth in claim 8 , wherein the light emitted from the radiation-to-light conversion material is essentially free of any radiation from the radiation source.
11. The system of claim 8 , wherein the radiation source comprises a light emitting diode containing an InGaN active layer and having a peak emission wavelength between 370 and 405 nm.
12. The system of claim 8 , wherein: the radiation source comprises a source of ultraviolet radiation.
13. A white light illumination system consisting essentially of:
an orange light emitting phosphor; and
a blue-green light emitting phosphor; and
wherein the orange light emitting phosphor and the blue-green light emitting phosphor are arranged to be excited, via the absorption of radiation from an ultraviolet radiation source, to produce orange light and blue-green light which blend to appear as white light to a human observer.
14. The system set forth in claim 13 , wherein the orange light emitting phosphor has a peak emission wavelength of about 590 nm; and wherein the blue-green light emitting phosphor has a peak emission wavelength of about 480 to about 500 nm.
15. The system as set forth in claim 13 , wherein the light emitted from the illumination system is essentially free of any radiation from the radiation source.
16. The system of claim 13 , wherein the radiation source comprises a light emitting diode containing an InGaN active layer and having a peak emission wavelength between 370 and 405 nm.