SOURCE CONDITIONING FOR IMAGING DIRECTIONAL BACKLIGHTS

摘要

Disclosed is an imaging directional backlight apparatus for providing large area uniform directed illumination from localized light sources. Within an exemplary optical valve system, a waveguide comprises a stepped structure, where the steps comprise extraction features hidden to guided light, propagating in a first forward direction. Returning light propagating in a second backward direction may be refracted, diffracted, or reflected by the features to provide discrete illumination beams exiting from the top surface of the waveguide. Such controlled illumination may provide for efficient, multi-user autostereoscopic displays as well as improved 2D display functionality. Illumination uniformity is provided by the positioning, packaging, and optically modifying of individual input sources. The latter employs non-imaging and refractive optics.