白光LED极限流明效率的计算

对蓝光芯片加黄色荧光粉制备白光LED方法的流明效率进行了理论计算。根据光度学原理,我们考虑到视觉函数V(λ)的修正,以色坐标为x=0.325,y=0.332,显色指数为81.5,色温为5 914 K的白光LED发光光谱为依据,计算了白光LED流明效率的理论极限:得出每瓦白光LED辐射光功率产生的光通量为298.7 lm,白光LED发射的总光子数为2.7×10¹⁸。在理想情况下,注入一个电子-孔穴对产生一个蓝光光子,设荧光粉的量子效率为1,因此,注入的电子-孔穴对数亦等于白光光子数,进而计算出白光LED每辐射1 W的光功率所需的电功率为1.51 W,上述白光LED发光光谱对应的白光LED的电-光转换的理论极限流明效率为197.8 lm/W。

Calculation of Theoretical Limitation of Lumen Efficiency for White LED

The luminous flux efficiency of white LED combining blue LED chip and YAG[DK(]∶[DK)]Ce yellow phosphor was calculated theoretically. According to the principle of photometry and considering the modification of the vision function V(λ), the theoretical limitation of luminous flux efficiency for white LED was calculated from the emission spectrum of the white LED at the condition of the chromaticity coordinate x=0.325, y=0.322, the rendering index 81.5, and the color temperature 5 913 K. The result showed that the luminous flux for LW white LED radiation power output is 298.7 lm and the total photons are 2.7×10¹⁸. If under ideal conditions, one electron-hole pair injected yields one blue photon and the quantum efficiency of the phosphor equals one, the numbers of electron-hole pair must equal to the numbers of white photons. So LW white LED radiation power output has to consume 1.51 W electric powers and the luminous flux efficiency limitation of electrical to optical conversion for the white LED is 197.8 lm/W at above condition.