Effects of parametric uncertainty in designing a high-brightness LED light system

One way to create white light is with a RGB color mixing system, in which light from multiple monochromatic LEDs (red, green and blue) is mixed. Unfortunately, there are several variations/uncertainties between individual LEDs that can create unwanted problems, such as variations in: forward voltage drop, peak wavelength, spectral radiant intensity, and the width of the spectral power distributions (SPD) of the LEDs. This paper will explain, through experiments, behavioral models and probability theory, how the variations affect the design of LED based lighting system. We especially describe the effects such as the influence of SPD variation and Forward Voltage drop variation.