SiO2 Powder: A Novel Solution for Improving Spatial Color Uniformity of White LED Lamps

This study proposes the addition of SiO2 scattering-particles into the phosphor layer of a multi-chip white light LED (MCW-LED) for enhancing its performances. It is demonstrated by computer simulations that SiO2 particles can bring significant effects on the correlated color temperature (CCT) uniformity and luminous flux. Through the simulation experiments, it is found that the MCW-LED with hybrid SiO2 structure with SiO2 particle size around 1 mu m can achieve higher color uniformity than other package structures. We investigate the influence of SiO2 (quartz) concentration on the CCT and the output flux of the MCW-LED with CCTs 7000, 7700 and 8500 K, respectively. Comparing with the LED package without SiO2, SiO2 packages can shrink the CCT deviation about 48 %. In the study, it is demonstrated that the participation of about 5-10 % SiO2 can accomplish the MCW-LED with higher spatial color uniformity and optimal lumen output.