Laminated composite of ceramic/glass films to realize high luminous efficiency and high color quality in laser-driven white lighting

Abstract

As for high-power laser diode (LD) driven lighting, Y₃Al₅O₁₂:Ce³⁺ phosphor ceramics (YAG:Ce-CPs) are regarded as ideal converters to produce white light. Due to the lack of the red component, it is still one of the biggest challenges to obtain high-quality light for YAG:Ce-CPs in LD lighting. In this work, CaAlSiN₃:Eu²⁺ phosphor-in-glass-films (CASN:Eu-PiGFs) are introduced to offset the emitting spectrum of YAG:Ce and suitable glass powders are employed as the inorganic binder to fabricate CASN:Eu-PiGFs. After coating CASN:Eu-PiGFs, a broad emitting spectrum (from 500 to 750 nm) is achieved. The luminous performances and thermal stability are optimized by modifying the CASN:Eu content in PiGF. In LD lighting, high luminous flux (858 lm) and luminous efficiency (165 lm W⁻¹) can be obtained. Meanwhile, owing to the remedy of the emitting spectrum, a high color render index (CRI, 82) is acquired for YAG:Ce-CPs in LD lighting. The strategy makes big progress in designing phosphor converters and will inspire more researchers to pursue high-quality white light in LD-driven lighting.