White-light LED clusters with high color rendering.

We established a model for spectra of LEDs at different drive currents. The simulation program of color rendering of white-light LED clusters has been developed, according to the principle of additive color mixture. The experimental results show that white/red LED clusters can realize color temperature untunable white light with a high color rendering index and high luminous efficacy and that neutral-white/red/blue LED clusters can realize color temperature tunable white light with a high color rendering index and high luminous efficacy.