Flexure Light Engine Alignment for Binocular Image Convergence
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Solution Overview
Problem
Mass-produced Light Engines (LEs) and waveguides in binocular systems suffer from manufacturing and assembly tolerances, leading to boresight errors and angular deviations that cause eye fatigue and inability to converge images, with existing solutions reducing Field of View (FOV) or increasing device size and complexity.
Innovation Solution
A flexure-based mechanical attachment system provides six degrees of freedom for precise alignment of components, allowing for accurate adjustment and fixation of light engines and waveguides, minimizing the need for additional components and maximizing FOV.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If digital offsets are used to align images, then alignment accuracy is improved, but Field of View is reduced
Solution Approach 1:
The patent replaces the digital offset alignment method with a mechanical alignment system using a flexure mechanism. The flexure provides passive mechanical alignment through elastic deformation, eliminating the need for digital image shifting and preserving the full Field of View while achieving sub-pixel alignment accuracy.
Solution Approach 2:
The flexure mechanism changes the physical position and orientation parameters of the light engine mechanically rather than digitally. By altering the mechanical configuration through elastic deformation, the system achieves alignment without the trade-off of losing Field of View that occurs with digital cropping or offsetting.
2Measurement precision
If monocular subassembly is used for alignment, then alignment precision is improved, but device size and complexity increase
Solution Approach 1:
The patent merges the alignment function into the existing monocular subassembly structure by integrating a flexure mechanism directly into the light engine mounting. This eliminates the need for separate alignment mechanisms or additional components, reducing assembly complexity while maintaining alignment precision through the flexure's six degrees of freedom.
Solution Approach 2:
The flexure mechanism serves multiple functions simultaneously: it provides mechanical support, enables alignment adjustment through elastic deformation, and accommodates manufacturing tolerances. This multi-functionality eliminates the need for separate alignment components, reducing overall device complexity.
3Stability of the object's composition
If rigid attachment is used for light engine mounting, then structural stability is improved, but alignment accuracy deteriorates
Solution Approach 1:
The patent transitions from a static rigid attachment to a dynamic flexure-based attachment that can adapt its configuration. The flexure allows the light engine to be positioned with high precision during assembly by elastically deforming to accommodate tolerance variations, then maintains stable positioning once aligned, combining the benefits of both rigidity and adaptability.
Solution Approach 2:
The flexure mechanism enables controlled changes in position and orientation parameters of the light engine through elastic deformation. This allows the system to compensate for manufacturing tolerances and achieve precise alignment without requiring perfectly rigid components, while still maintaining structural stability after alignment.
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 ensures accurate alignment with minimal offset, reducing eye fatigue and discomfort by maintaining image convergence within user-friendly tolerances while minimizing device size and assembly complexity.
Implementation Method 1
A method of aligning a component (e.g., a light engine) to a support structure (e.g., a waveguide or frame) using a flexure
Data Source
AI summary
A light engine alignment system for a head-mounted device comprises a light engine, a flexure coupled to the light engine, the flexure used to position the light engine at a particular alignment to set a projection axis, and a fastener to affix the light engine to the head-mounted device at the particular alignment set by the flexure.