High extinction ratio polarized light guide with layered cross stacking nanostructure

Cross stacking of aluminum and PMMA strip nanostructure has been proposed as a reflective polarizer on the top surface of a solid light guide plate for polarization recycling in order to increase the efficiency of a side edge type backlight module for liquid crystal display. In order to exploit the range of light incident angle on the layered nanostructure with high extinction ratio, a dedicated backlight illumination optics for LED light source has been designed for controlling the light propagation direction within the light guide while achieving satisfactory uniformity in the meantime. The illumination optics features a reflective cup in front of the LED source and one-dimensional V-groove on the bottom surface of the light guide as the light extraction pattern. Ray tracing simulation has shown that a 4 in. diagonal light guide with proposed architecture has achieved uniformity of 75% while having the extracted light well constrained within the range of incident angle on the layered nanostructure where extinction ratio above 1000 can be obtained. (C) 2009 Elsevier B.V. All rights reserved.