不同驱动模式下白光LED光色电性能分析

Analysis on optoelectric and colorimetric properties of white LEDs under the different drive mode

采用脉冲和直流两种驱动模式分别驱动同一批次的白光LED灯珠,对比分析了在"视觉亮度"一致时两种情况下的光色电性能,并研究了人眼视觉惰性对白光LED性能的影响。研究发现,在低脉冲占空比下,脉冲驱动LED的电流和发光效率比直流驱动的低,并且随着占空比的增加,两者的差值逐渐减小并趋于相等;当脉冲占空比高于70%时,两者驱动电流的差值增加,而脉冲驱动的发光效率却高于直流驱动的发光效率。此外,相比直流驱动,高脉冲电流驱动下的LED的发光更接近等能白光,进而增强了人眼对LED发光亮度的刺激响应,有效地提高了人眼的"视觉亮度"。

White LED lamp beads with the same performance parameters are driven by pulse circuit and DC circuit, respectively, and their optoelectric and colorimetric properties are analyzed comparatively when the visual luminance is considered to be equal. The effect of the visual inertia of human eyes on the properties of white LEDs is investigated. It can be found that：when the duty cycle is lower than 70%, the current and luminous efficiency of the pulse driven LED is lower than that of the DC drive, and with the further increase of duty cycle, the difference value tends to be small; when the duty cycle is over 70%, the difference of drive current become again large and the luminous efficiency of the pulse drive is higher than that of the DC drive. This phenomenon is well explained based on and light attenuation properties of LED. In addition, compared with the DC drive, white LEDs with high pulse current drive are closer to the white lighting of equal energy, thus enhancing the stimulus responses of human eyes and increasing the “visual luminance” of human eyes.