Pixelated phosphors for high-resolution and high-contrast white light sources.

Porous phosphor microstructures are studied for their potential as light converter in laser-based, high-resolution lighting systems. Phosphor particles are filled into pre-patterned silicon molds and coated by an atomic layer deposition with a thin layer of Al2O3 for mechanical stability. Pixel sizes of 2 mm by 2 mm down to 25 µm by 25 µm are fabricated. The structures show a significant drop in luminance between the illuminated and the non-illuminated, adjacent pixel. The high thermal conductivity of the silicon allows an efficient cooling of the structures. Having removed the backside silicon, an active air flow cooling of the porous phosphor structure is possible.