Colorful diffractive luminaires providing white light illumination

摘要

Extended area lighting devices include a light guide and diffractive surface features on a major surface thereof. The diffractive surface features include diffractive features of different pitches in non-overlapping regions of the major surface tailored to extract guided-mode light of different colors from the light guide in different directions. The diffractive features extract light such that an ordinary user observes substantially different colors in different regions of the light guide, providing a colorful appearance. Notwithstanding this, the diffractive features also extract light such that the lighting device illuminates a reference surface, disposed at an intermediate distance from the light guide, with illumination light that is substantially uniform in color and substantially white. Optical films having diffractive features that can be used to construct such devices and light guides are also disclosed. The concept can also be extended to embodiments in which the uniform color illumination light is not substantially white.

主权项

1. A luminaire, comprising:
a light guide having an optical axis and a first major surface, the first major surface having a plurality of diffractive surface features therein adapted to couple guided-mode light out of the light guide; and one or more light sources disposed to inject light into the light guide; wherein the plurality of diffractive surface features comprise diffractive surface features of different pitches; wherein the diffractive surface features extract guided-mode light from the light guide such that an ordinary user of the luminaire observes substantially different colors in different regions of the light guide at a viewing geometry; and wherein the diffractive surface features and the light source(s) in combination are tailored to provide illumination of a substantially uniform color at a reference surface of interest perpendicular to the optical axis and separated from the light guide by an intermediate distance D, and wherein the substantially uniform color is also substantially white.