Directional flat illuminators

Abstract

Disclosed is an optical valve or light valve for providing large area collimated illumination from localized light sources, and system and method thereof for 2D, 3D, and / or autosteroscopic displays. An optical valve may include a stepped structure, in which the steps include separated extraction features which may be optically hidden to light propagating in a first direction. Light propagating in a second direction may be refracted, diffracted, or reflected by the features to provide illumination beams exiting from the top surface of the optical valve. Such controlled illumination may provide for efficient, multi-user autostereoscopic displays as well as improved 2D display functionality.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This is a continuation application of and claims priority to U.S. patent application Ser. No. 13 / 300,293, filed Nov. 18, 2011 entitled “Directional flat illuminators” which claims priority to U.S. Provisional Patent Application No. 61 / 415,810, filed Nov. 19, 2010, entitled “Directional flat illuminators,” the entirety of which are herein incorporated by reference.TECHNICAL FIELD[0002]This disclosure generally relates to illumination of light modulation devices, and more specifically relates to light guides for providing large area directed illumination from localized light sources for use in 2D, 3D, and / or autostereoscopic display devices.BACKGROUND[0003]Spatially multiplexed autostereoscopic displays typically align a parallax component such as a lenticular screen or parallax barrier with an array of images arranged as a first and second set of pixels on a spatial light modulator. The parallax component directs light from each of the set...

AI Technical Summary

Benefits of technology

The present patent describes a method and apparatus for guiding light using an optical valve. The optical valve allows light to propagate in a first direction with low loss and also allows some light to reflect and exit the valve in a second direction. The valve has a first and second light guiding surface, with guiding features and extraction features connected to each other. The extraction features allow light to pass through with low loss in both directions. The optical valve system may include an illuminator array and a sensor for detecting an observer in the proximity of viewing windows of the valve. The technical effects of the invention include efficient, multi-user autostereoscopic displays and improved 2D display functionality.

Problems solved by technology

Gaps between the pixels, for example, for electrodes, typically produce non-uniform viewing windows.

Undesirably, such displays exhibit image flicker as an observer moves laterally with respect to the display and so limit the viewing freedom of the display.

Such flicker can be reduced by defocusing the optical elements; however such defocusing results in increased levels of image cross talk and increases visual strain for an observer.

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