Accelerated reliability test method for optics in LED luminaire applications

A high accelerated stress testing (HAST) system is introduced to study the photo-thermal stability and reliability of remote phosphor plates, made from Bisphenol-A polycarbonate (BPA-PC) and YAG. Remote phosphor plates, combined with a blue-light LED source, are used to produce white light with a correlated colour temperature (CCT) of 4000 K. In this study, the remotephosphor BPA-PC samples of 3 mm thickness were photo-thermally aged at temperature range 80 to 120 °C. The blue light is radiated on the sample with light intensity of 13200 W/m
²
. Thermal quenching of the YAG samples is also studied. It is shown that crystallographic structure of phosphor is stable during thermal ageing.