Exellent Color Quality and Luminous Flux of Wleds Using Triple-Layer Remote Phosphor Configuration

Abstract

This study proposed a triple-layer remote phosphor (TRP) structure to improve the color and luminous ux of white LEDs (WLEDs). TRP structure consists of 3 di erent phosphor layers: yellow YAG:Ce layer below, red CaMgSi2O6:Eu ,Mn phosphor on top and green layer Ba2Li2Si2O7:Sn ,Mn phosphor in the middle. Using red CaMgSi2O6:Eu ,Mn to control the red light component leads to the increase in color rendering index (CRI). Utilizing the green CaMgSi2O6:Eu ,Mn phosphor to control the green light component results in the increase in luminous e cacy (LE) of WLEDs. Furthermore, when the concentration of these two phosphors increased, yellow layer YAG:Ce concentration decreased to maintain average correlated color temperatures (ACCTs) in the range from 6000K to 8500K. Besides CRI and LE, color quality scale (CQS) is also analyzed through the control of green and red phosphors concentrations. The research results show that the higher the concentration of CaMgSi2O6:Eu ,Mn is, the better the CRI becomes. In contrast, CRI decreased signi cantly when increasing the concentration of Ba2Li2Si2O7:Sn ,Mn . Meanwhile, CQS achieved notable enhancement in the concentration range of 10% -14% CaMgSi2O6:Eu ,Mn, regardless of Ba2Li2Si2O7:Sn ,Mn concentration. LE, in particular, can also increase by more than 40% along with the improvement of CRI and CQS due to the reduction of the backscattered light and the addition of green light. Research results are a valuable reference for producers who wish to improve the color quality and enhance the luminous ux of WLEDs.