Improved efficacy of warm-white light-emitting diode luminaires

We present a novel approach to address one of the technical hurdles the current light-emitting diode (LED) lighting field faces: the packaged efficacy of warm-white LEDs is 20%-30% lower than that of cool-white LEDs depending on the color rendering index. With a differentiated luminaire design in combination with a new class of nano materials, we have greatly improved the efficacy of warm white by 15% at the luminaire system level, which translates to less energy being required to achieve the same light output, and thus offers a more energy-efficient solution. Reliability test of the luminaire shows no performance degradation within the tested period of more than 3000 h. A modeling has been developed to predict the optical performance of luminaires incorporating the nano materials, which agrees well with the experimental data and serves as a powerful tool for designing luminaires with targeted performance.