Method and Apparatus for Generating Input Images for Holographic Waveguide Displays

Abstract

An image generation device comprises: a spatial light modulator; a source of light; a beam deflector; an illumination waveguide and an image transport waveguide, each waveguide containing at least one switchable grating; and a coupler for directing scanned light into a first set of TIR paths in said illumination waveguide. A switchable grating in the illumination waveguide diffracts light onto said SLM, a switchable grating in said image transport waveguide diffracting image-modulated from the SLM into a waveguide path.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation of U.S. patent application Ser. No. 15 / 512,500, entitled “Method and Apparatus for Generating Input Images for Holographic Waveguide Displays,” filed Jun. 29, 2015, which is a U.S. National Phase of PCT Application No. PCT / GB2015 / 000203, filed Jun. 29, 2015, which claims the priority of U.S. Provisional Patent Application No. 62 / 071,277, entitled “Method and Apparatus for Generating Input Images for Holographic Waveguide Displays,” filed Sep. 19, 2014, the disclosures of which are incorporated herein by reference in their entireties.BACKGROUND OF THE INVENTION[0002]This invention relates to an apparatus for generating an image, and more particularly to an apparatus for generating an input image for a holographic waveguide display.[0003]The invention addresses the problem of providing uniform output illuminination in holographic waveguide displays. U.S. patent application Ser. No. 13 / 844,456 entitled TRAN...

AI Technical Summary

Benefits of technology

The system effectively reduces contrast of banding artifacts, providing high illumination uniformity and efficient coupling of image content into holographic waveguides, enhancing display performance by minimizing chromatic dispersion and brightness variations across the field of view.

Problems solved by technology

The device exhibits near 100% efficiency with no voltage applied and essentially zero efficiency with a sufficiently high voltage applied.

Reducing the thickness of the grating leads to a decrease in the diffraction efficiency and a broadening of the diffraction efficiency angular bandwidth.

A major design challenge is coupling the image content into the waveguide efficiently and in such a way the waveguide image is free from chromatic dispersion and brightness non uniformity.

However, lasers and other narrow band sources such as LEDs suffer from the problem of pupil banding artifacts which manifest themselves as output illumination non uniformity.

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