On Choosing Phosphors for Near-UV and Blue LEDs for White Light

Abstract

As the lighting industry transitions from traditional technologies to solid state lighting (SSL), it appears that the most preferred way to generate white light using SSL technology has been to use phosphor-converted light emitting diodes (pc-LEDs). There has been considerable debate in the literature whether near-UV LEDs or blue LEDs should be used to excite phosphors for white light. Quite often, in the phosphor literature, the efficiencies of LEDs from 365 nm to 470 nm are somewhat neglected in this debate. In this paper, we have provided data on external quantum efficiency of In_xGa_1-xN LEDs over the above spectral range, and use these data together with phosphor performance to compare near-UV and blue based approaches to making white light pc-LEDs. We also use simulations to discuss white light blends at two different correlated color temperatures (3000 K and 4000 K) for both LED configurations.