Patent attributes
Common approaches to retroreflectors rely on absorptive materials that waste light energy that could be utilized for visibility. Disclosed photoluminescent retroreflectors filter reflected light, like traditional colored retroreflectors, but down-convert photons of the wrong color into a glow visible from more directions. The glow enables visibility for more observers or observers whose light source is far from their line of sight. The color of the glow can be adjusted by choice of luminescent material as a design feature or safety purpose. Certain embodiments utilize photoluminescent additives within a retroreflector while other embodiments utilize a photoluminescent coating on top of a pre-made retroreflector. An exemplary photoluminescent material for these optical devices is CuInZnS2 quantum dots.
