Image Light Guide Diffractive Optics Light Security
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Solution Overview
Problem
Conventional image light guide systems for near-eye displays often output light in undesired directions, which can be aesthetically undesirable and compromise concealment in military applications, while also not providing adequate control over light distribution for commercial and general consumer use.
Innovation Solution
An image light guide system incorporating an in-coupling diffractive optic to encode image-bearing light and an out-coupling diffractive optic to decode and expand light in specific directions, combined with optical devices like liquid crystal shutters and photonic crystal shields to manage and reduce light output in undesired directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional image light guide arrangements are used, then the system provides significant reduction in bulk, weight, and overall cost, but light is output in more directions than the direction of the viewer eyebox
Solution Approach 1:
The patent applies local quality by implementing an optical device at specific locations within the light guide system to selectively control light output. The optical device is positioned to address particular directions where unwanted light emerges, allowing localized modification of light distribution without changing the entire system architecture. This enables targeted suppression of light in undesired directions while preserving the compact and cost-effective design of the conventional light guide.
Solution Approach 2:
The optical device acts as an intermediary element between the light guide optics and the external environment. It mediates the light output by selectively blocking or redirecting light in undesired directions while allowing light in the desired eyebox direction to pass through. This intermediary approach resolves the contradiction by introducing a controlling element that manages light distribution without fundamentally altering the underlying light guide structure.
2Object-generated harmful factors
If light security is implemented to control and eliminate light output in undesired directions, then aesthetic improvement and concealment are achieved, but the system complexity increases
Solution Approach 1:
The patent extracts the light control function into a separate optical device that can be independently optimized and positioned. Rather than integrating light control throughout the entire light guide system, the solution extracts the security function into a discrete component that blocks unwanted light directions. This extraction reduces the complexity burden on the main light guide architecture while achieving the desired light security effects.
Solution Approach 2:
The light guide system is segmented into functional zones: the primary light guide optics for image delivery and separate optical devices for light security control. This segmentation allows each component to be optimized independently - the light guide maintains its compact design while the optical devices provide targeted light control. The modular segmentation reduces overall system complexity by distributing functions across independent components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively directs light towards the eyebox while minimizing light output in unwanted directions, enhancing aesthetic appeal and operational security by controlling light distribution efficiently.
Implementation Method 1
An in-coupling diffractive optic formed along the waveguide, wherein the in-coupling diffractive optic is operable to diffract a portion of the image-bearing light beams from the image source into the waveguide in an angularly encoded form
Implementation Method 2
an out-coupling diffractive optic formed along the waveguide, wherein the out-coupling diffractive optic is operable to expand the portion of image-bearing light beams, direct a first portion of expanded image-bearing light beams from the waveguide in an angularly decoded form in a first direction toward an eyebox
Implementation Method 3
an optical device operable to reduce, eliminate, and/or block the second portion of expanded image-bearing light beams output from the image light guide in the second direction
Data Source
AI summary
A light secure image light guide including an image source operable to generate image-bearing light beams and a waveguide operable to propagate the image-bearing light beams. An in-coupling diffractive optic formed along the waveguide, wherein the in-coupling diffractive optic is operable to diffract a portion of the image-bearing light beams from the image source into the waveguide in an angularly encoded form, and an out-coupling diffractive optic formed along the waveguide, wherein the out-coupling diffractive optic is operable to expand the portion of image-bearing light beams, direct a first portion of expanded image-bearing light beams from the waveguide in an angularly decoded form in a first direction toward an eyebox, and direct a second portion of expanded image-bearing light beams from the waveguide in a second direction different from said first direction. The image light guide further including an optical device operable to reduce, eliminate, and/or block the second portion of expanded image-bearing light beams output from the image light guide in the second direction.