Spectral optimization of warm-white light-emitting diode lamp with both color rendering index (CRI) and special CRI of R9 above 90

The optimal spectra of the warm-white LED (WWLED) lamp consisting of AlGaInP red LED and the p-W LED packaged by combining silicate green and orange phosphors with a InGaN blue LED die was obtained by nonlinear program for maximizing the luminous efficacy of radiation while both color rendering index (CRI) and special CRI of R9 for strong red above 90 at correlated color temeratures (CCTs) of 2700 K. The optimal peak wavelengths of red LED, blue LED die, silicate green and orange phosphors are 626 nm, 454 nm, 535 nm and 584 nm, respectively. Their optimal relative radation fluxs are 9.7%, 33.4 %, 26.1 %, 30.8 %, respectively. The real WWLED lamp with CCT of 2653 K, CRI of 90, R9 of 94 and R(9-12) of 88, as well as luminous efficacy (LE) of 80.2 lm/W have been realized. Furthermore, the WWLED lamp can realized CCT tunable warm-white-light with CRIs of 86 ∼ 93, R9s of 86 ∼ 95 and LEs of 78.2 ∼ 80.3 lm/W at CCTs of 2392 K to 3014 K by adjusting drive current of the red LED.