Toward High‐Quality Laser‐Driven Lightings: Chromaticity‐Tunable Phosphor‐in‐Glass Film with “Phosphor Pattern” Design

Abstract

High‐quality laser‐driven lightings require not only high luminous flux (LF) but also uniform spectral distribution. Herein, the green‐emitting Lu3Al5O12:Ce3+ (LuAG:Ce) and red‐emitting CaAlSiN3:Eu2+ (CASN:Eu) commercial phosphor powders with high‐performance are fabricated into phosphor‐in‐glass film (PiGF) sintered on sapphire plate, and further served as a motor‐driven rotatory “phosphor wheel” to receive pumping of blue laser in a reflective excitation light path. The greatly relieved thermal pressure, benefited from the high‐thermal‐conductivity sapphire substrate and the pulse‐like rotatory excitation mode, efficiently retards the occurrence of luminescence saturation. Remarkably, the photon reabsorption phenomenon in the conventional “phosphor mixture” design is well solved by introducing a smart “phosphor pattern” design, free of causing inhomogeneous angular color distribution at the same time. The constructed LuAG:Ce PiGF‐based lighting source yields high brightness of 2970 lm@21 W mm−2, and the constructed LuAG:Ce PiGF‐CASN:Eu PiGF‐based lighting source yields luminosity‐chromaticity balanced white light with LF higher than 1000 lm and color rendering index of 80–90.

Laser Phosphors for Next-Generation Lighting Applications

“…Laser-driven white light sources show great advantages in terms of super luminance, small beams, and compactness. They can find broad applications in automotive headlights, searchlights, projectors, laser TVs, visible-light communications, and medical endoscopes. − Owing to the development of high-performance yellow-emitting laser phosphors, super luminance laser-driven white light sources, fabricated by combining yellow-emitting laser phosphors with blue LDs, have already been applied in long-distance lighting applications. Bicolor PiG films containing green and red phosphors, showing great potential for medical endoscopes, allow one to realize tunable color temperatures of 2500–6300 K and a high Ra value of 95, but the luminous flux is only 287 lm .…”

Reducing the cyan-cavity: Lu2MAl4SiO12:Ce3+ (M = Mg, Ca, Sr and Ba) phosphor-in-glass film towards full-spectrum laser-driven lighting

“…On the other hand, the ''phosphor wheel'' design is able to greatly reduce heat accumulation in the color converter due to the boosted heat convection to the air and the pulse-like excitation. 37 Here, the ''phosphor wheel'' was 4 cm in diameter and adhered onto an aluminum micro-motor operated at 3000 rpm (inset of Fig. 5b), receiving blue laser in a reflective light path.…”

A highly stable CsPbBr3–SiO2glass ceramic film sintered on a sapphire plate for laser-driven projection displays

“…This patterning design could effectively separate the two luminescent centers, and thus reduced the photon reabsorption. 52,53 As shown in Fig. 5b, excited by a blue laser with 600 mW mm À2 power density in rotating mode (the rotation speed was This journal is © The Royal Society of Chemistry 2022 6000 rpm min À1 ), the as-fabricated lighting prototype could produce RGB colors with narrow band simultaneously and achieve a wide color gamut up to 131.6% of NTSC and 98% of Rec.…”