High-Brightness Phosphor-Converted White LDs With High Color Rendering Through Sapphire@Bi-Color PiGF@Sapphire Converter

To realize both high luminance and excellent color rendering for laser lighting, a novel phosphor-converted white laser diode (pc-wLD) was proposed by combining blue laser diode (LD) chips and a sapphire@ bi-color phosphor-in-glass film (PiGF)@sapphire (SA@ BPiGF@SA) converter. The SA@BPiGF@SA was fabricated by sintering mixed green/red PiGF between two transparent sapphire plates, making efficient double-sided heat dissipation channel for laser-driven PiGF. The optical performance of SA@BPiGF@SA-based wLD was optimized by adjusting the contents of YAGG and CASN phosphors. The SA@BPiGF@SA-based wLD achieves a warm white light with a high color rendering index (CRI) of 83.6, a correlated color temperature (CCT) of 4548 K, and a luminous flux (LF) of 208.5 lm. The SA@BPiGF@SA enables a highest LF of 1436 lm under a saturation threshold of 27 W, which is 61.3% higher than the traditional BPiGF@SA (890 lm@17 W). Furthermore, the working temperature of SA@BPiGF@SA is only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$51.1~^{\circ }$ </tex-math></inline-formula>C under 15-W laser excitation, while that of BPiGF@SA reaches up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$313~^{\circ }$ </tex-math></inline-formula>C. The results suggest that the SA@BPiGF@SA-based wLD is a potential laser-driven white lighting source, enabling high luminance and excellent light color quality.