The analysis of MF resin and CaCO3 diffuser-loaded encapsulations to enhance the homogeneity of correlated color temperature for phosphor-converted LEDs

Abstract

The most popular method used in the production of phosphor-converted LEDs (pc-LEDs) is dispensing phosphor freely. However, this method is inferior in generating good angular correlated color temperature (CCT) homogeneity. Thus, in this article, a diffuser-loaded encapsulation is proposed as a potential solution for better CCT uniformity. The paper provides a detailed investigation on how melamine formaldehyde (MF) resin and CaCO₃ loaded encapsulations impact the uniformity of CCT, as well as the lumen efficacy of pc-LEDs. The results demonstrate that between MF resin and CaCO₃ loaded encapsulations, the MF resin yields a higher light diffusion efficiency while the CaCO₃ maintains greater lumen efficacy. The photon scattering development is the key force behind the enhancement of the angular CCT uniformity in pc-LEDs’ output when using the loaded encapsulations of MF resin and CaCO₃ particles. Since this package utilized mineral, it has reasonable cost and is quite easy to control while still being effective in enhancing the angular CCT homogeneity of pc-LEDs. Diffusers with 1% concentration of MF resin or 10% concentration of CaCO₃ are determined as an optimal solution for reducing the variance of angular CCT and increasing the lumen output.