Optical Waveguide Layering With Beam Splitting for Uniform AR Images
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Solution Overview
Problem
Conventional AR diffractive waveguide designs face challenges in achieving uniformity of coupled images due to high processing complexity and limitations in micro/nano processing, leading to uneven light distribution and reduced luminous efficiency.
Innovation Solution
An optical waveguide structure with at least two laminated layers and a beam splitting structure between layers to manage light propagation, allowing different parts of light beams to be reflected or transmitted at varying steps, reducing propagation step and enhancing uniformity without increasing design complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional AR diffractive waveguide design changes groove shape, groove depth and refractive index of grating to improve image uniformity, then image uniformity is improved, but processing complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent divides the waveguide into multiple layers (first waveguide layer, second waveguide layer, third waveguide layer) with different groove depths. Each layer processes a portion of the light beam, segmenting the overall light control function across multiple simpler structures rather than requiring one complex high-precision grating structure
Solution Approach 2:
The patent changes the depth parameter of grooves across different layers (first groove depth, second groove depth, third groove depth) to create a stepped structure. This parameter variation allows each layer to contribute differently to light beam processing, achieving uniformity through cumulative effect rather than single high-precision structure
2Ease of manufacture
If conventional design uses uniform groove depth and shape throughout the waveguide, then manufacturing is simpler, but image uniformity and luminous efficiency deteriorate
Solution Approach 1:
The waveguide is segmented into multiple layers with progressively different groove depths. The first layer has shallow grooves for initial light processing, the second layer has medium grooves for intermediate processing, and the third layer has deep grooves for final processing. This segmentation allows each layer to be manufactured with moderate precision while collectively achieving high overall uniformity
Solution Approach 2:
The patent transitions from a single-plane grating structure to a multi-layer stepped structure in the depth dimension. By adding the vertical layering dimension with varying groove depths, the system achieves three-dimensional light control that improves uniformity without requiring extreme precision in any single layer
3Manufacturing precision
If the propagation step in the waveguide is reduced to improve uniformity, then image uniformity improves, but the waveguide structure becomes more complex
Solution Approach 1:
The propagation path is segmented across multiple layers. Instead of reducing the propagation step in a single layer (which would require complex curvature or refraction), the patent distributes the propagation across first, second, and third layers with progressively deeper grooves. Each layer handles a portion of the propagation distance, achieving effective step reduction through segmentation rather than structural complexity
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
Improves image uniformity and luminous efficiency by simplifying the process, preventing adverse effects from propagation step differences, and reducing grating design complexity while ensuring uniformity across different fields of view.
Implementation Method 1
a coupling-in grating provided on the first surface or the second surface and configured to allow received parallel light beams to enter the optical waveguides
Implementation Method 2
the parallel light beams being propagated in the optical waveguides in a total-reflection manner at a first propagation step
Data Source
AI summary
The present disclosure provides an optical waveguide structure, including: at least two layers of optical waveguides; a coupling-in grating configured to allow received parallel light beams to enter the optical waveguides, the parallel light beams being propagated in the optical waveguides in a total-reflection manner at a first propagation step; a beam splitting structure configured to allow a first part of light beams to be reflected in such a manner that the first part of light beams are propagated at a second propagation step, and allow a second part of light beams to be transmitted in such a manner that the second part of light beams are propagated at the first propagation step, the second propagation step being different from the first propagation step; and a coupling-out grating configured to extract the light beams propagated in total-reflection manner in the at least two layers of optical waveguides.