Color Consistency Enhancement of White Light-Emitting Diodes Through Substrate Design

We demonstrate a new kind of substrate structure to enhance the correlated color temperature (CCT) consistency of white light-emitting diodes through controlling the liquid morphology by the wetting theory. Based on this method, the effect of the coating phosphor volume variation on CCT can be effectively reduced. Numerical simulations and experiments on the dispensing process with different phosphor gel volumes are conducted. The results show that the height fluctuation of the phosphor layer on the new substrate is 54.5% of that on the conventional substrate when the dispensed phosphor gel volume changes from 3.38 to 4.98 μl. The optical simulation results show that compared with the conventional structure, the CCT consistency of the new substrate is improved by 42.3%.