An intensively lit collimating unit for the realization of a mosaic‐structured large‐scale RGB backlight
K. Käläntär · Journal of the Society for Information Display · 2006
Abstract— To realize a large‐scale LCD backlight, a hexagon‐shaped single‐side micro‐structured light guide was developed. Three of the micro‐structured light‐guide plates are stacked and combined with a circular prism sheet (CPS) to form a unit backlight. The light guides couple azimuth light radiation from a side‐emitting LED that is mounted at the center of the light guides to air through a CPS in order to make a plane source out of a point source. The combination of stacked functional light guides with a CPS transforms convex toroidal‐shaped light radiation into a narrow cone whose center axis is perpendicular to the back surface of the liquid‐crystal panel. The light efficiency of the illumination unit is about 78% and the full‐width at half maximum of the collimated light is about 2 and 32.5° in the azimuth and radial directions, respectively.