Unique Strategy for Achieving Excellent Luminous Efficiency and High Saturation Threshold for High-Power Laser–Driven Lighting

Abstract

Laser-driven lighting offers high brightness and excellent directivity and is widely employed in laser projection and automobile headlights. However, the phosphor conversion materials currently used in laser-driven lighting suffer from low light-extraction efficiency and poor thermal conductivity. Herein, a unique phosphor-in-glass(PiG)–silver (Ag)–copper (Cu) (referred to as PAC) converter that comprises a four-layer structure is reported: high-doped phosphor-in-glass (PiG) layer, high-reflectivity silver film, sealing silver paste, and copper substrate. Due to its unique design, the sample with an 85 wt% doping concentration and a 0.2 mm thickness exhibits outstanding luminescent performance, achieving a LE of 298 lm W−1 and a luminous flux (LF) of 2873 lm at an input power of 11.54 W. Furthermore, in the rotational mode, a high LF of 3920 lm is achieved. These results demonstrate that the PAC converter holds promise for applications in high-power laser lighting.

Keywords: Laser-driven lighting, Luminous efficiency, Thermal stability, Multilayer structure, Phosphor-in-glass (PiG)