为了研究在中间视觉范围内,驱动电流对LED光通量的影响,运用LED光色电综合分析仪测量了白、蓝、绿、黄和红色LED从12mA到24mA的辐射谱,然后结合国际照明学会推荐的中间视觉模型,计算了在不同亮度水平下的光通量,进而得到光通量随电流的变化规律。研究表明:对于白、绿、蓝色LED,光通量随亮度水平的降低而增大,随电流的增大而线性增大,光通量随电流变化的速率随着亮度水平的降低而增大。黄色和红色LED的光通量虽然也随着驱动电流的增加而线性增大,但是,随着亮度水平的降低,光通量不断减小,且随电流变化的速率也不断减小。该研究对中间视觉下使用的LED灯具的驱动电路和调光器设计具有重要意义。
In order to analyze the effect of driving current on luminous flux at different mesopic light level, radiant spectra of white, blue, green, yellow and red LEDs with the driving current from 12 mA to 24 mA are measured with the photometric, chromatic and electric characteristics analyzer, and then combined the mesopic model recommended by CIE, the mesopic luminous flux and its change with current are obtained. It is shown that the luminous flux of white, green and blue LED increase as the light level and the driving current decreases, and the darker, the faster the rate of increment is. The luminous flux of yellow and red LED also increase linearly as the current increases. Therefore, the rate of increment decreases as the light level reduces, so as to decrease the luminous flux. This research is very important for the design of driving circuit and modulator of LED lamps.