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US 2019/0293858 A1Published application
Optical waveguide for directional backlight
AssigneeRealD Spark, LLC
InventorsGraham J. Woodgate, Michael G. Robinson
Life of this patent
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Abstract
A switchable directional backlight for a privacy display comprises a waveguide with first and second opposing input ends and a turning film arranged to collect light output from the waveguide for input into a spatial light modulator. The waveguide has an array of light deflecting features arranged on one guiding surface and an opposing planar surface. Light deflecting features are arranged such that light input from the first input end is output with a narrow angular range and light input from the second input end is output with a wide angular range.
Claims25
An optical waveguide comprising:
- first and second opposed light guiding surfaces for guiding light along the optical waveguide by total internal reflection;
- and
- at least one light input end arranged between the first and second light guiding surfaces, wherein the light input end extends in a lateral direction,
- wherein the second light guiding surface comprises:
- (i) a plurality of non-inclined light extraction features arranged in an array, each non-inclined light extraction feature being elongate, extending in a longitudinal direction perpendicular to the lateral direction, and having surface normal directions that vary in a plane orthogonal to the longitudinal direction and that have no component of tilt in the longitudinal direction;
- and
- (ii) a plurality of inclined light extraction features arranged in an array, each inclined light extraction feature having a surface normal direction with a tilt that has a component in the longitudinal direction,
- the plurality of non-inclined light extraction features and the plurality of inclined light extraction features being oriented to direct guided light through the first and second light guiding surfaces as output light.
5 more elements
Dependencies are inferred from the claim text.