Microsphere Spaced Waveguide Display for AR
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Solution Overview
Problem
Diffractive waveguides for augmented and virtual reality displays face reduced efficiency and luminance contrast at the edge of the field of view due to limited angular bandwidth, causing virtual holograms to fade, which affects the realism and clarity of the see-through experience.
Innovation Solution
A waveguide display constructed with separated parallel optical substrates joined by a pressure-sensitive adhesive containing microspheres, which ensures accurate mechanical spacing and enhances luminance uniformity by expanding the exit pupil, improving the see-through clarity and realism of virtual content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If diffractive waveguides are used for augmented reality displays, then the field of view is provided, but the luminance contrast and efficiency are reduced at the edge of the field of view
Solution Approach 1:
The waveguide is divided into multiple separate parallel optical substrates instead of using a single continuous waveguide structure. This segmentation allows each substrate to be independently optimized and positioned, enabling better control over light propagation paths and improving luminance uniformity across the field of view while maintaining angular bandwidth.
2Illumination intensity
If multiple optical substrates are used to expand the exit pupil, then the luminance uniformity is improved, but the mechanical spacing precision becomes more difficult to maintain
Solution Approach 1:
A pressure-sensitive adhesive layer is introduced as an intermediary between the multiple optical substrates. This adhesive serves as a mechanical spacer that maintains precise spacing between substrates while allowing for easy assembly and disassembly. The pressure-sensitive nature enables controlled bonding without requiring complex fixation mechanisms, thereby maintaining manufacturing precision.
3Illumination intensity
If the exit pupil is expanded from a small entrance pupil, then the luminance uniformity across the field of view is enhanced, but the device complexity increases
Solution Approach 1:
Multiple optical substrates are merged into a single integrated waveguide assembly that functions as one unified optical system. The pressure-sensitive adhesive bonds the substrates together to form a compact structure that expands the exit pupil while maintaining a manageable form factor. This merging approach distributes the optical function across multiple elements while presenting a simplified interface for assembly and integration.
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 effectively increases the exit pupil size from a small entrance pupil, maintaining high luminance uniformity and enhancing the realism of virtual content across the entire field of view, addressing the inefficiencies of diffractive waveguides.
Implementation Method 1
The substrates are joined by an adhesive configured to have suspended therein a plurality of hard microspheres
Implementation Method 2
a plurality of hard microspheres which ensure accurate mechanical spacing between the respective substrates
Implementation Method 3
The waveguide may be constructed of first and second optical substrates, and a pressure sensitive adhesive including embedded microspheres joining and spacing the substrates apart from each other
Data Source
AI summary
The technology provides a waveguide display including an optical waveguide comprising a plurality of separated parallel optical substrates. The substrates are joined by an adhesive configured to have suspended therein a plurality of hard microspheres. The adhesive may be a pressure sensitive adhesive designed to have suspended therein the microspheres. Microspheres may have diameters on the order of a few microns up to 100 microns. The waveguide may be constructed of first and second optical substrates, and a pressure sensitive adhesive including embedded microspheres joining and spacing the substrates apart from each other. Additional substrates may be provided. The technology also provides a method of manufacturing a waveguide.