Variance of radiometric performances for cool-white and neutral-white LED luminaries

Correlated color temperature (CCT) affecting feelings must be adequately adjusted according to the change of atmosphere. White light-emitting diode (LED) spectral for solid state lighting should be designed for high luminous efficacy as well as good color rendering index (CRI). In different applications, when warm-white or cool-white LED's are recommended, we are forced to use also dimmers. In this paper, cool-white and warm-white LEDs resulting from phosphor converted blue (PCB) chips with a wavelength peak of 445 nm and 598 nm are experimented. The tests pursued the radiometric parameters as correlated color temperature, color rendering (Ra) and chromaticity coordinates (x, y) while varying the parameters of the power supply for cool-white LED XPE-CREE 6500 and neutral-white LED XPL4000.