Highly Reliable WLEDs With All-Inorganic Packaging Structure by Soldering Phosphor-in-Glass

In this letter, highly reliable white light-emitting diodes (WLEDs) were fabricated by using an all-inorganic packaging structure with a phosphor-in-glass (PiG) converter. The PiG was soldered on a three-dimensional substrate to realize the hermetic structure for WLEDs. The packaging structure displays the reliable and dense bonding layer between the PiG and the substrate. The thickness of phosphor glass layer was controlled to adjust the optical performances of WLEDs. At the thickness of $170~\mu $ m, the fabricated WLED achieves a white light with a luminous efficiency (LE) of 88.5 lm/W, a correlated color temperature (CCT) of 5274 K, and a color rendering index (CRI) of 67. After the accelerated aging test, the LE of fabricated WLEDs is only reduced by 9% and the related light quality shows no obvious shift.