Thermal Issues of a Remote Phosphor Light Engine

In the quest for mechanisms to improve the light extraction efficiency and luminous efficacy of solid state lighting, the remote phosphor concept has emerged as a potential solution. Such a concept consists in bringing the phosphor element at a remote location from the LED chip. Early, this technology was propelled by two premises: a) it allows the phosphor to operate at a lower temperature and, therefore, increases its conversion efficiency; and b) it allows backscattered light to be redirected towards the target. This paper addresses the first premise by experimentally comparing the operating phosphor temperature in the intimate and remote phosphor configuration applied to the light engine approach. Results show that, for the topologies tested, the phosphor operates at a lower temperature in the remote phosphor configuration than in the intimate phosphor one.