Efficient transmissive remote phosphor configuration for a laser-driven high-luminance white light source

Abstract

To realize laser-driven high-luminance white light sources, many reflective configurations have been studied, often resulting in a challenging optical design. In this paper it is demonstrated that the efficacy of a transmissive configuration can be significantly enhanced by using a sapphire half-ball lens as out-coupling optic. This lens not only improves efficiency, but also drastically increases the potential light output due to improved heat dissipation from the single-crystal phosphor converter. Both claims are substantiated with detailed experimental results and realistic opto-thermal simulations, showing a light output of 6550 lm and over 20000 lm, respectively and corresponding luminance of 67 MCd/m2 and 209 MCd/m2.

All-inorganic color converter based on a phosphor in bismuthate glass for white laser diode lighting

“…[14][15][16] Due to the high laser power density and a small radiation spot of the blue laser diode, the fluorescent layer is subject to high laser radiation energy and fluorescent conversion heat, resulting in high temperature in the spot position of the fluorescent layer. [17][18][19][20] The traditional fluorescent layer is a mixture of a phosphor and an organic resin. Due to the poor heat resistance and low thermal conductivity of organic resin, the problem of resin carbonization and thermal quenching of the phosphor occurs at high temperatures, which makes the organic fluorescent layer meet the packaging requirements of white light laser diodes.…”

Enhancing luminous flux and color rendering of laser-excited YAG:Ce3+ single crystal phosphor plate via surface roughening and low-temperature sintering a CaAlSiN3:Eu2+ phosphor-in-borate glass

“…Phosphor/silicone composite is widely used as a color converter in LEDs, however, it is limited used in pc-WLD as its low thermal stability. The optical density of an LD is extremely high reach up to 6.9 W/mm 2 [10]. Excessive optical density will cause the thermal quenching and carbonization of phosphor/silicone composites [11].…”

“…To enhance forward light extraction efficiency, Rondelez et al proposed a novel optical scheme in which the SCP was fixed on a sapphire half-ball lens [10], which resulted in a 150% improvement in luminous flux. Wagner et al [25] revealed that the photoluminescence intensity of transmissive white laser light source improves with the increase in the roughness of the surface of the phosphor.…”