LIGHT EXTRACTING DIFFUSIVE HOLOGRAM FOR DISPLAY ILLUMINATION

摘要

This disclosure provides systems, methods and apparatus for illumination, such as for illuminating displays, including reflective displays. An illumination device (210) includes a light-extracting, diffusive holographic medium (280). The holographic medium may be a holographic film and may be disposed on the surface of a light guide (230), and includes a hologram (282) that both extracts light out of the light guide and diffuses this extracted light for propagation towards the display elements (261) of the display (260). The hologram extracts light by redirecting light, which is propagating within the light guide, so that the light propagates out of the light. The diffusion occurs upon the light being redirected, as the hologram redirects the light towards the light guide in a controlled range of angles.