The high-color-rendering (HCR) potential of the light sources consisting of 350-nm ultraviolet light-emitting diodes (UV-LED) and three-basal-color phosphors was simulated and experimentally confirmed. By using an AlGaN-based UV-LED as an excitation source at the 350-nm wavelength, we measured fluorescence spectra of three-basal-color phosphors, and simulated the optimum phosphor mixture based on the Commission Internationale de l’Eclairage standard light sources D75, D65, D55, D50, C, and A, with HCR indexes (Ra) over 92. We confirmed the potential of HCR of this light source consisting of 350-nm UV-LED and three-basal-color phosphors, by obtaining Ra=86∼89 of the incandescent type of standard light source A experimentally. Such high Ra are due to the highly monochromatic UV-LED emission and the wide spectral separation between the UV excitation (350 nm) and visible fluorescences. This combination also provides a diffusive, nonglare light source with highly steady color independent of the emission orient...
[1]
Shuji Nakamura,et al.
The Blue Laser Diode: GaN based Light Emitters and Lasers
,
1997
.
[2]
Naoki Kobayashi,et al.
346 nm Emission from AlGaN Multi-Quantum-Well Light Emitting Diode
,
1999
.
[3]
Naoki Kobayashi,et al.
Efficient and high-power AlGaN-based ultraviolet light-emitting diode grown on bulk GaN
,
2001
.
[4]
Takashi Mukai,et al.
Phosphor-Conversion White Light Emitting Diode Using InGaN Near-Ultraviolet Chip
,
2002
.
[5]
Naoki Kobayashi,et al.
GaN-free transparent ultraviolet light-emitting diodes
,
2003
.