Phosphor materials and combinations for illumination-grade white pcLEDs

Blue III-nitride based power LEDs have opened the way for Light Emitting Diodes to penetrate the illumination market. Most wanted seem to be warm white, high color rendering devices. Phosphor-converted LEDs, which meet these requirements, have been recently announced and sampled; they will be put into the context of possible other solutions and for the first time discussed in some detail.