Design, manufacturing and experimental validation of a bonded dual-component microstructured system for vertical light emission

This article presents a bonded dual-component microstructured planar device made of acrylic glass for vertical light emission. It features optical, cone-like undercut microstructures for efficient illumination from a light guiding plate. This microstructured light guide is designed with the help of numerical raytracing simulations for the use as an innovative luminaire for room lighting. It can also find application in display technology for efficient backlight units. To realize such undercut microstructures in acrylic glass, a variothermal injection molding process, complemented by an ultraviolet radiation assisted thermal bonding procedure is introduced. By modifying the glass transition temperature of a thin surface layer of the microstructures the undercut microstructures can be bonded thermally to a light guiding plate without any glue or solvent, while the shape of the microstructures is perfectly preserved. Measurements verify the high bonding quality and confirm the good correspondence between measured light emission and ideal optical simulations.