Micro-molded Prism Waveguide Segmentation for Optical Uniformity
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Solution Overview
Problem
The manufacture of geometric waveguides for virtual and augmented reality devices is challenging due to issues such as non-uniform light output, black lines, and ghost images, which are caused by imperfections in the coating and alignment of transflective mirrors.
Innovation Solution
The geometric waveguide is designed with active components like expansion and decoupling elements, which are independently manufactured and processed. This allows for tailored molding and coating operations for each transflective mirror, followed by optimized alignment and assembly, enabling batch processing, lower costs, and improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If transflective mirrors are manufactured and coated together as a single unit, then alignment may be simpler, but manufacturing precision and performance are degraded due to coating imperfections and alignment issues
Solution Approach 1:
The waveguide is divided into multiple separate transflective mirror elements that are manufactured and coated independently, then assembled together. This segmentation allows each element to be optimized separately, achieving higher manufacturing precision while managing complexity through modular assembly processes.
2Reliability
If complex coating architectures with multiple layers are used to achieve desired reflection/transmission ratios, then optical performance is improved, but manufacturing complexity and cost increase due to multiple masking and deposition steps
Solution Approach 1:
Different transflective mirror elements are coated with different reflection/transmission ratios tailored to their specific positions in the waveguide. This local quality approach ensures uniform light output across the entire waveguide while avoiding the need for complex multi-layer coatings on all elements, thereby reducing manufacturing complexity.
3Productivity
If batch processing is implemented for independent manufacturing of waveguide components, then productivity increases and costs decrease, but manufacturing precision may be compromised
Solution Approach 1:
Alignment features and positioning structures are incorporated into the mold designs during the preliminary manufacturing stage. This allows batch processing of mirror elements while maintaining precision through pre-built alignment mechanisms, resolving the conflict between productivity and manufacturing precision.
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 independent manufacturing and processing of waveguide components result in higher yield and performance, reducing imperfections like non-uniformity, black lines, and ghost images, thereby enhancing the quality of virtual and augmented reality images.
Implementation Method 1
an expansion zone configured to expand an image beam entering the waveguide through the input prism along a first dimension and a second dimension orthogonal to the first dimension
Implementation Method 2
transported therethrough by total internal reflection (TIR)
Data Source
AI summary
A method of manufacturing a micro-molded prism geometric waveguide includes forming a first transflective mirror element and a separate second transflective mirror element, forming a first functional coating over an active surface of the first transflective mirror element, forming a second functional coating over an active surface of the second transflective mirror element, and aligning the first transflective mirror element with the second transflective mirror element to form a microprism array.