Effects of remote sediment phosphor plates on high power laser-based white light sources

Phosphor-converted blue laser diodes are regarded as the next-generation high-brightness solid-state lighting sources. However, it is difficult to obtain white light with high angular color uniformity due to the Gaussian distribution of the laser light sources. Meanwhile, laser excitation power density of the light source is high, which would bring serious heating effects to the phosphor layers. In this study, a strategy has been proposed to solve the problem by using remote sediment phosphor plates. In detail, we have compared the effects of remote sediment/non-sediment phosphor plates to the phosphor-converted blue laser diodes on the overall light output characteristics, angular optical distribution properties, as well as their thermal performance. The emission from sediment phosphor samples has been found more divergent, and angular deviation in the correlated color temperature of the emitted light could be greatly reduced from 1486 to 294 K, yet with only 5% luminous flux loss, as compared to non-sediment phosphor samples. Most importantly, the sediment phosphor sample pushes the power damage threshold up to 588.1 W/cm² (non-sediment sample: 512.3 W/cm²). Our work has demonstrated the sediment phosphor plates would ameliorate the angular color uniformity for the laser-based lighting source, while extending its lifespan with improved thermal stability.