A Novel Approach to Characterize Phosphor Particles for the Color Tuning of WLEDs

A novel approach was proposed to characterize the optical performance of phosphor particles based on a laser particle analyzer (LPA). For Sr₃SiO₅:Eu phosphor, under single scattering condition, the angular scattering pattern was determined based on the measured radiant powers by detector arrays located at different scattering angles in the LPA, while the relationship between scattering coefficients and phosphor concentrations was obtained by measured obscuration ratios. Ray-tracing simulations were undertaken, employing the measured optical parameters as inputs. The transmittance measurement setup was built based on a goniophotometer, and 3528 commercial white light-emitting diodes (WLEDs) were packaged with the phosphor and silicone in different mixing ratios. The simulated transmittances and spectral power distributions for WLEDs were compared with measurements to verify the effectiveness of the characterized scattering parameters. The developed methodology may be used to optimize phosphors for the color tuning of WLEDs.