Design of lithium disilicate glass-ceramic based highly thermally stable LuAG:Ce PiG green converter for dynamic laser illumination†

Abstract

Phosphor-in-glass (PiG) is widely used in laser illumination because of its low-temperature sintering process and high luminous efficiency. The selection of the glass matrix is essential for achieving high stability in PiG and preserving the original properties of the phosphor particles within it. In this study, a novel lithium disilicate glass-ceramic (LDGC) was developed as a matrix material. A series of LDGC-LuAG PiGs were synthesized at low temperatures using a one-step sintering method. The precipitation of lithium disilicates (LDs) greatly enhanced the thermal stability of the material. The LDGC-LuAG PiG exhibits an impressive thermal conductivity of 3.5 W m⁻¹ K⁻¹, a luminous efficiency (LE) as high as 246 lm W⁻¹, and a maximal luminous flux (LF) of 1584 lm with a conversion efficiency (CE) reaching up to 69%. Furthermore, the LDGC-LuAG PiG color wheel was developed and encapsulated in a commercial dynamic laser illumination module. At 190 W of blue input power, a bright green light was produced with a surprising LF of 19 654 lm, which even exceeded the commercial silicone color wheel. This study is expected to create new prospects for high-power laser illumination.