Optical Waveguide Pupil Redistribution for Image Uniformity
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Solution Overview
Problem
Augmented reality display systems using optical waveguides face challenges with non-uniform intensity distributions and pupil replication, leading to undesirable dark and light fringes and blotches in the replicated images.
Innovation Solution
An optical waveguide apparatus with an input-coupler, a first intermediate-component, a second intermediate-component, and an output-coupler, where the second intermediate-component is a diffractive component that performs pupil redistribution, enhancing the uniformity of light intensity and overlap of pupils within the waveguide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional waveguide pupil replication is used, then image transmission is achieved, but non-uniform intensity distribution occurs causing dark and light fringes and blotches
Solution Approach 1:
The waveguide is divided into multiple functional zones with different optical components: input coupler, first intermediate component, second intermediate component, and output coupler. Each zone performs a specific function in the pupil replication process, allowing independent optimization of light distribution at different stages to achieve uniform intensity across the entire output pupil.
Solution Approach 2:
Different intermediate components are positioned at specific locations within the waveguide to create localized optical transformations. The first intermediate component addresses horizontal pupil distribution while the second intermediate component addresses vertical pupil distribution, allowing tailored light redistribution in different spatial regions to eliminate fringes and blotches.
2Device complexity
If simple TIR-based light transport is used, then device complexity is reduced, but pupil overlap and image uniformity deteriorate
Solution Approach 1:
Two intermediate components are introduced as intermediary optical elements between the input and output couplers. These intermediaries perform partial pupil expansion and redistribution functions that bridge the gap between simple TIR transport and complex diffractive pupil replication, achieving uniform pupil overlap with moderate complexity.
Solution Approach 2:
The optical design transitions from two-dimensional TIR-based light transport to three-dimensional pupil manipulation by introducing intermediate components that perform pupil expansion in both horizontal and vertical dimensions. This dimensional expansion enables comprehensive pupil overlap and uniform intensity distribution across the output pupil.
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 solution improves the uniformity of the replicated image, reducing non-uniformities and enhancing the overall image quality by increasing the overlap of pupils, thus providing a more coherent and smooth image viewing experience.
Implementation Method 1
The output-coupler is configured to couple, out of the optical waveguide, the light corresponding to the image that has traveled through the optical waveguide from the input-coupler to the output-coupler at least in part by way of total internal reflection (TIR)
Implementation Method 2
The second intermediate-component is a diffractive component located between the first-intermediate component and the output-coupler and is configured to perform pupil redistribution on a portion of the light corresponding to the image before the portion of the light reaches the output-coupler
Data Source
AI summary
An optical waveguide including an input-coupler, a first intermediate-component, a second intermediate-component and an output-coupler is described herein. The input-coupler couples, into the waveguide, light corresponding to an image associated with an input-pupil and directs the light toward the first intermediate-component. The first intermediate-component performs horizontal or vertical pupil expansion and redirects the light corresponding to the image toward the output-coupler. The second intermediate-component is a diffractive component located between the first-intermediate component and the output-coupler and performs pupil redistribution on a portion of the light corresponding to the image before the portion reaches the output-coupler. The output-coupler performs the other one of horizontal or vertical pupil expansion and couples, out of the waveguide, the light corresponding to the image. Related methods and systems are also described.