Phosphor-in-glass film sintered on sapphire lens for laser welding hermetic packaging of high-power white LEDs

White light-emitting diodes (WLEDs) represent a revolutionary type of energy-saving and environmentally friendly light source, which has been extensively employed in a multitude of lighting and display applications. Nevertheless, traditional organic packaging is unable to fulfill the requirements of highly reliable high-power WLEDs, including hemertic property, heat resistance, and excellent luminous properties. Herein, an allinorganic hermetic packaging based on laser-localized welding and phosphor-in-glass film sintered on a sapphire lens (PiGF-SL) has been developed for high-power WLEDs. The PiGF-SL with a Kovar frame was welded to a three-dimensional direct-plated ceramic (3D-DPC). The high-strength and crack-free welded joint with a shear strength of 258.83 MPa and packaging cavity with excellent gas tightness (leakage rate 8.6 x 10(-10) Pa m(3)/s) were simultaneously obtained, resulting in the high-power WLED capable of maintaining its excellent optical properties for an extended period in harsh environments. Furthermore, the optical performance of welded WLEDs was optimized by adjusting the PiGF-SL film thickness and red CaAlSiN3:Eu2+ (CASN) phosphor content. The welded WLED emits a cool white light by improving the PiGF thickness to 91 mu m and exhibits high color quality with red CASN phosphor content of 8 wt%, which simultaneously presents outstanding color rendering index (CRI) of 91, luminous efficacy (LE) of 44.8 lm/W, and correlated color temperature (CCT) of 4322 K. Following a 200-h aging process, the laser-welded PiGF-SL-based WLED exhibited a slightly reduced efficiency loss and a stable color quality in comparison to reflow-soldered and epoxy-bonded WLEDs. Our work provides valuable guidance and solutions for the highly reliable and board-level packaging of WLEDs.