中性色温下两基色、三基色荧光粉转换白光LED的光谱优化

针对中性色温4 870 K,考虑斯托克斯损失,研究了两基色、三基色的白光LED的光谱优化。结果表明:InGaN/GaN基蓝光LED激发YAG荧光粉合成的白光光视效能可高达483.5 lm/W,但显色性较差,计算的斯托克斯效率为83.9%。加入窄带红色荧光粉或红光LED,优化后的光视效能降低为343 lm/W,但显色指数升至94.7,同时计算得到该LED的斯托克斯效率为84.4%。对该优化的三基色LED光谱进行可调色温白光的特性分析,发现较高色温 (＞4 000 K)对应的显色指数普遍高于低色温(＜4 000 K)的显色指数。

Spectrum Optimization of Bi-color and Tri-color Phosphor-converted White LEDs in Neutral Correlated Color Temperature System

The spectra of the bi-color and tri-color phosphor-converted white LED were optimized in the neutral correlated color temperature of 4 870 K with consideration of Stokes shift energy loss.The results showed that a high luminous efficacy of radiation up to 483 lm/W could be attained in the case of the white LED composed of blue chip and YAG phosphor but with a poor color quality and 83.9% Stokes efficiency.When a narrow-band red phosphor or LED chip was added to the bi-color white LED,a good color rendering index of 94.7 was gained with a reduced luminous efficacy of radiation 343 lm/W and a Stokes efficiency of 84.4%.Later,we characterized the performance of tunable-color-temperature tri-color white LED.It was found that the color rendering index was better when the correlated color temperature exceeded 4 000 K.