The dependences of light efficiency of radiation （LER） and color-rendering index （CRI） of trichromatic white light-emitting diode （wLED）, composed of blue LED die, green/yellow, and red phosphors, on the peak wa...The dependences of light efficiency of radiation （LER） and color-rendering index （CRI） of trichromatic white light-emitting diode （wLED）, composed of blue LED die, green/yellow, and red phosphors, on the peak wave- length of each primary were investigated by theoretical calculations, at correlative color temperature （CCT） from 2,700 to 6,500 K. The peak wavelength of InGaN based blue LED chip ranges from 450 to 471 nm, while those of Ca3Sc2Si3012：Ce3＋, b-SiA1ON：Eu2＋, and Y3A15012：Ce3＋ based green/yellow phosphors range from 511 to 572 nm, and those of Sr2SisN8：Eu2＋ and CaA1SiN3：Eu2＋ red phosphors range from 620 to 650 nm, which cover almost all the practically used, commercially available wave bands until now. Then, based on the results, selection guides of peak wavelengths for blue LED chip and phosphors to obtain tradeoff LER 〉280 lm.W-1 as well as CRI 〉80 in all CCTs are proposed. The favorable wave bands of each primary are suggested.展开更多
In this study, small- and large-particle-diameter phosphor powders were mixed together（hybrid phosphors）to balance light efficacy and angular color uniformity and pursue optimal results. Phosphor with small-particle...In this study, small- and large-particle-diameter phosphor powders were mixed together（hybrid phosphors）to balance light efficacy and angular color uniformity and pursue optimal results. Phosphor with small-particlediameter of 4 lm was employed and it was mixed into each large-particle-diameter phosphor of 10, 16, 22, and 26 lm,at mass percentage from 0 % to 50 % with an interval of10 %, respectively. Remote phosphor package was adopted and overall phosphor concentration was kept constant for better comparison. Moreover, absorption coefficient labs,scattering coefficient lscaand extinction coefficient lext of each hybrid phosphors were calculated based on Mie theory to further discuss the experiment results. Results show that, the introduction of small-particle-diameter phosphor to large one can highly improve angular color uniformity while only slightly reduce light efficacy. The optimal performance with angular color uniformity of91.6 % as well as normalized light efficacy of 95.7 % is achieved in the white light emitting diode with hybrid phosphors consisting of 60 wt% powder of 22 μm and40 wt% powder of 4 μm.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51272027)
文摘The dependences of light efficiency of radiation （LER） and color-rendering index （CRI） of trichromatic white light-emitting diode （wLED）, composed of blue LED die, green/yellow, and red phosphors, on the peak wave- length of each primary were investigated by theoretical calculations, at correlative color temperature （CCT） from 2,700 to 6,500 K. The peak wavelength of InGaN based blue LED chip ranges from 450 to 471 nm, while those of Ca3Sc2Si3012：Ce3＋, b-SiA1ON：Eu2＋, and Y3A15012：Ce3＋ based green/yellow phosphors range from 511 to 572 nm, and those of Sr2SisN8：Eu2＋ and CaA1SiN3：Eu2＋ red phosphors range from 620 to 650 nm, which cover almost all the practically used, commercially available wave bands until now. Then, based on the results, selection guides of peak wavelengths for blue LED chip and phosphors to obtain tradeoff LER 〉280 lm.W-1 as well as CRI 〉80 in all CCTs are proposed. The favorable wave bands of each primary are suggested.
基金financially supported by the National Natural Science Foundation of China (No. 51272027)
文摘In this study, small- and large-particle-diameter phosphor powders were mixed together（hybrid phosphors）to balance light efficacy and angular color uniformity and pursue optimal results. Phosphor with small-particlediameter of 4 lm was employed and it was mixed into each large-particle-diameter phosphor of 10, 16, 22, and 26 lm,at mass percentage from 0 % to 50 % with an interval of10 %, respectively. Remote phosphor package was adopted and overall phosphor concentration was kept constant for better comparison. Moreover, absorption coefficient labs,scattering coefficient lscaand extinction coefficient lext of each hybrid phosphors were calculated based on Mie theory to further discuss the experiment results. Results show that, the introduction of small-particle-diameter phosphor to large one can highly improve angular color uniformity while only slightly reduce light efficacy. The optimal performance with angular color uniformity of91.6 % as well as normalized light efficacy of 95.7 % is achieved in the white light emitting diode with hybrid phosphors consisting of 60 wt% powder of 22 μm and40 wt% powder of 4 μm.
