Luminous output improvement in chip scale packaged Ce3+:YAG-based ceramic phosphors-converted white LEDs via laser assistance for application in automobile headlights

In this study, two kinds of composite ceramic phosphors, Ce 3+ :YAG/Al 2 O 3 and Ce 3+ :Y(Gd)AG/Al 2 O 3 were prepared via solid state reaction sintering in flowing pure oxygen at atmospheric pressure. The ceramic phosphors were packaged into chip-scale white light emitting diodes (w-LEDs), and laser assisted w-LED automobile headlight prototypes were assembled. The luminous flux output of the w-LEDs was significantly improved through additional blue diode laser excitation. Notably, the Al 2 O 3 phase is able to impart an improvement in the luminescence saturation exhibited by Ce 3+ :Y(Gd)AG, which typically reaches saturation prior to Ce 3+ :YAG.