DIFFRACTIVE LIGHTING DEVICES WITH 3-DIMENSIONAL APPEARANCE

摘要

Extended area lighting devices include a light guide and diffractive surface features on a major surface of the light guide. The diffractive surface features provide low distortion for viewing objects through the light guide. Light from discrete light source(s) is injected into the light guide, and the diffractive surface features interact with the injected light to couple guided-mode light out of the light guide. The out-coupled light produces one or more bands whose apparent shape changes with viewing position. The bands may be bright bands that correspond to the discrete light sources, or dark bands associated with an optional non-uniform reflective structure extending along a side surface of the light guide. Multiple bands may form a pattern that changes with viewing position, the pattern of bands having a 3-dimensional appearance for at least some viewing positions. The lighting devices can be used as luminaires for general lighting or decorative lighting.