Optical performance improvement of phosphor-in-glass based white light-emitting diodes through optimized packaging...

To improve the optical performance of multi-component phosphor-in-glass (PiG) based white light-emitting diodes (WLEDs), we proposed an optimized packaging structure, which is a combined structure of a patterned PiG with a crater-type lens. The patterned PiG yields a red phosphor circle surrounded by a yellow phosphor concentric ring. Comparison simulations and experiments between the conventional mixed structure, patterned structure, and proposed structure were conducted. Compared with the mixed structure and patterned structure, the luminous efficacy of the proposed structure is increased by 19.3% and 10.7% at the driving current of 350 mA, respectively. Furthermore, the deviation of the correlated color temperature (CCT) of the patterned PiG is reduced from 906 to 129 K by the crater-type lens at the average CCT of 4100 K. The results demonstrate that the proposed packaging structure can improve the luminous efficacy and angular color uniformity (ACU) of a PiG-based WLED simultaneously.