β‐SiAlON:Eu2+ Phosphor‐in‐Glass Film: An Efficient Laser‐Driven Color Converter for High‐Brightness Wide‐Color‐Gamut Projection Displays

Abstract

AbstractThe green‐emissive laser phosphor is urgently demanded for projection displays to compensate the “Green Gap.” Herein, the well‐known β‐SiAlON:Eu2+ with admirable luminescent feature is incorporated into robust silicate glass matrix, cosintered on sapphire plate, and then constructed into “phosphor wheel,” succeeding in retaining excellent green‐emissive performance and meanwhile relieving the luminescence droop at high pumping density of blue laser. Probing the local effect of laser–matter interaction reveals that the luminescence saturation is majorly determined by thermal quenching, but the influence of intensity quenching cannot be ignored. Systematical works are performed to optimize glass composition, cosintering procedure, sample parameters, and optical path, turning out the maximal quantum efficiency of 60%, thermal conductivity of 9.5 W m−1 K−1, and high saturation threshold far beyond 22 W mm−2. In a proof‐of‐concept experiment, accompanied with red laser diode, the constructed light engine yields a high brightness with luminous flux of 1310 lm (luminance of 880 Mcd m−2), a low étendue of ≈1.5 mm2, and a wide color gamut of 112.5% National Television System Committee (NTSC), demonstrating the composite material as an efficient laser‐driven color converter for projection displays.