High color rendering white light emitting devices and high color rendering photoluminescence compositions
A exemplary light emitting device includes an excitation source operable to generate excitation light with a dominant wavelength in a range 450 nm to 470 nm; a red photoluminescence material which generates light with a peak emission wavelength in a range 600 nm to 620 nm with a full width at half maximum emission intensity greater than 70 nm and less than 80 nm; a yellow to green photoluminescence material which generates light with a peak emission wavelength in a range 530 nm to 550 nm; and a narrow-band red photoluminescence material which generates light with a peak emission wavelength in a range 625 nm to 635 nm with a full width at half maximum emission intensity greater than about 5 nm and less than about 25 nm.
1. A light emitting device that emits white light with a color temperature from 2700K to 5000K and a CRI Ra of at least 90, comprising:
an LED that generates blue excitation light with a dominant wavelength from 450 nm to 470 nm;
a broadband red nitride-based phosphor of general composition (Sr,Ca)SiAlN 3 :Eu which, in response to stimulation by the excitation light, generates light having a peak emission wavelength from 600 nm to 620 nm with a full width at half maximum emission intensity from 70 nm to 80 nm;
a yellow to green cerium-activated aluminum garnet phosphor which, in response to stimulation by the excitation light, generates light having a peak emission wavelength from 515 nm to 550 nm; and
a narrowband red manganese-activated fluoride phosphor which, in response to stimulation by the excitation light, generates light having a peak emission wavelength from 625 nm to 635 nm for the highest emission peak with a full width at half maximum emission intensity from about 5 nm to about 25 nm, wherein the narrowband red manganese-activated fluoride phosphor is selected from the group consisting of: K 2 SiF 6 :Mn 4+ , K 2 GeF 6 :Mn 4+ , and K 2 TiF 6 :Mn 4+ ;
wherein when said color temperature is from about 2700K to about 3000K the broadband red nitride-based phosphor comprises about 3 wt % of the combined weight of the broadband red nitride-based and narrowband red manganese-activated fluoride phosphors and the light emitting device has a luminous efficacy from 345 lm/W op to 355 lm/W op ;
wherein when said color temperature is about 4000K the broadband red nitride-based phosphor comprises about 2 wt % of the combined weight of the broadband red nitride-based and narrowband red manganese-activated fluoride phosphors and the light emitting device has a luminous efficacy of about 340 lm/W op ; and
wherein when said color temperature is about 5000K the broadband red nitride-based phosphor comprises about 1 wt % of the combined weight of the broadband red nitride-based and narrowband red manganese-activated fluoride phosphors and the light emitting device has a luminous efficacy of about 330 lm/W op .
2. The light emitting device of claim 1 , wherein the broadband red nitride-based phosphor has a peak emission wavelength of about 615 nm.
3. The light emitting device of claim 1 , wherein the yellow to green photoluminescence material generates light with a peak emission wavelength selected from the group consisting of: 515 nm to 530 nm, 530 nm to 540 nm, and 540 nm to 550 nm.
4. The light emitting device of claim 1 , wherein the yellow to green cerium-activated aluminum garnet phosphor is selected from the group consisting of: (Y,Lu) 3 (Al,Ga) 5 O 12 :Ce, Y 3 (Al,Ga) 5 O 12 :Ce, and Lu 3 Al 5 O 12 :Ce.
5. The light emitting device of claim 1 ,
wherein when said color temperature is from about 2700K to about 3000K the white light has a spectrum having a broad emission peak at about 565 nm;
wherein when said color temperature is about 4000K the white light has a spectrum having a broad emission peak at about 580 nm; and
wherein when said color temperature is about 5000K the white light has a spectrum having a broad emission peak at about 585 nm.
6. A light emitting device that emits white light with a color temperature from 2700K to 5000K and a CRI Ra of at least 90, comprising:
an LED that generates blue excitation light with a dominant wavelength from 450 nm to 470 nm;
a broadband red nitride-based phosphor of general composition (Sr,Ca)SiAlN 3 :Eu which in response to stimulation by the excitation light, generates light having a peak emission wavelength from 600 nm to 620 nm with a full width at half maximum emission intensity from 70 nm to 80 nm;
a yellow to green cerium-activated aluminum garnet phosphor which, in response to stimulation by the excitation light, generates light having a peak emission wavelength from 515 nm to 550 nm; and
a narrowband red manganese-activated fluoride phosphor which, in response to stimulation by the excitation light, generates light having a peak emission wavelength from 625 nm to 635 nm for the highest emission peak with a full width at half maximum emission intensity from about 5 nm to about 25 nm, wherein the narrowband red manganese-activated fluoride phosphor is selected from the group consisting of: K 2 SiF 6 :Mn 4+ , K 2 GeF 6 :Mn 4+ , and K 2 TiF 6 :Mn 4+ ;
wherein when said color temperature is from about 2700K to about 3000K the white light has a spectrum having a broad emission peak at about 565 nm and the light emitting device has a luminous efficacy from 345 lm/W op to 350 lm/W op ;
wherein when said color temperature is about 4000K the white light has a spectrum having a broad emission peak at about 580 nm and the light emitting device has a luminous efficacy of about 340 lm/W op ; and
wherein when said color temperature is about 5000K the white light has a spectrum having a broad emission peak at about 585 nm and the light emitting device has a luminous efficacy of about 330 lm/W op .
7. The light emitting device of claim 6 , wherein the broadband red nitride-based phosphor has a peak emission wavelength of about 615 nm.
8. The light emitting device of claim 6 , wherein the yellow to green photoluminescence material generates light with a peak emission wavelength selected from the group consisting of: 515 nm to 530 nm, 530 nm to 540 nm, and 540 nm to 550 nm.
9. The photoluminescence material composition of claim 6 , wherein the yellow to green cerium-activated aluminum garnet phosphor is selected from the group consisting of: (Y,Lu) 3 (Al,Ga) 5 O 12 :Ce, Y 3 (Al,Ga) 5 O 12 :Ce, Lu 3 Al 5 O 12 :Ce.