OPTICAL ELEMENT FOR USE IN AN ARRAY OF OPTICAL ELEMENTS IN A DISPLAY ARRANGEMENT

摘要

An optical element such as used in an array of such elements is configured as a truncated symmetrical solid structure having light input and output surfaces and sides tapering inwardly from the light input surface to the light output surface. The fraction of the input light which is outputted and the angular distribution of the output light vary as a function of said ratio and the tapering angle. Optimal geometries in terms of viewing angle, contrast and THROUGHPUT are for a ratio of the area of the output surface to the area of the input surface ranging between approximately 0.1 and approximately 0.3, and for tapering angles relative to the axis of the structure ranging between approximately 7.5 and approximately 17.5 degrees.