GaN-Based White-Light-Emitting Diodes with Low Color Temperature and High Color Rendering Index

The luminescence properties of high color rendering white LED depending on the proportions of mixed phosphor powders were investigated by adopting green and red phosphors stimulated by a 440 nm InGaN/GaN based blue LED. The results show that when the proportion of A/B type silica gels and green/red phosphor powders is 0.5 : 0.5 : 0.2 : 0.03, two luminance bands are stimulated and their wavelength peaks are 535 and 643 nm, respectively. The minimum color temperature can reach 3 251 K, while the color rendering is as high as 88.8. Compared with the traditional white LED fabricated by yellow YAG-phosphors-coated high efficiency 460 nm blue LED, the color temperature is lower and the color rendering index can be increased by almost 26%.