Compact collimators for high brightness blue LEDs using dielectric multilayers

A novel method is presented to inject the light of millimeter-sized high-brightness blue LEDs into light guides of submillimeter thickness. Use is made of an interference filter that is designed to pass only those modes that will propagate in the light guide by total internal reflection. Other modes are reflected back to the LED cavity and...

Dielectric multilayer angular filters for coupling LEDs to thin light guides

A new approach is described to couple light from high-power blue LEDs (1x1mm2) into a thin large area light guide using a dielectric interference multilayer as an angular filter. The goal is to achieve large area luminaires such as backlight systems. The method overcomes the drawback of structuring holes or recessions in light guides when using...

Injecting light of high-power LEDs into thin light guides

A new method using a thin-film multilayer filter is described to couple light from high-power LEDs into a thin light guide such as an LCD backlight. Light emitted below the critical angle is reflected back to the LED and recycled. Largeangle emitted light passes the filter and is transported by total internal reflection in the light guide. The...

Wire-grid diffraction gratings used as polarizing beam splitter for visible light and applied in liquid crystal on silicon

The application of wire grid polarizers as efficient polarizing beam splitters for visible light is studied. The large differences between the transmissivity for different polarizations are explained qualitatively by using the theory of metallic wave guides. The results of rigorous calculations obtained by using the finite element method are...