Polarization-Selective Lens Stacks for AR Accommodation-Vergence Alignment
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Solution Overview
Problem
Conventional augmented reality (AR) systems face challenges in providing a comfortable and natural presentation of virtual image elements amidst real-world imagery due to mismatches between accommodative and vergence states, leading to user discomfort.
Innovation Solution
An adaptive lens assembly with a polarization-selective lens stack comprising a birefringent and isotropic lens, configured to switch between different optical powers, is used to modify wavefront divergence and provide variable optical power, aligning accommodative and vergence cues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional AR systems present virtual image elements without adjusting optical power, then the system structure remains simple, but user discomfort occurs due to mismatch between accommodative and vergence states
Solution Approach 1:
The patent implements dynamic optical power adjustment through adaptive lens assemblies that can change their focal length in real-time. The lens assembly transitions from a static optical system to a dynamic one, allowing the optical power to be adjusted based on the distance of virtual objects, thereby resolving the accommodation-vergence mismatch while maintaining system manageability through controlled complexity.
Solution Approach 2:
The patent changes the optical parameters of the lens assembly by adjusting the spacing between lens elements or using liquid crystal variable focus lenses to modify refractive indices. This allows continuous variation of optical power to match different virtual object distances, improving user comfort without requiring complete redesign of the optical architecture.
2Adaptability or versatility
If multiple waveguides are used to provide different optical powers, then the optical power requirements are met, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges multiple waveguide functions into a single waveguide structure by incorporating an adaptive lens assembly that can dynamically adjust optical power. Instead of using separate waveguides for different focal lengths, one waveguide with a variable focus lens achieves the same versatility, reducing structural complexity and manufacturing difficulty while maintaining adaptability.
Solution Approach 2:
The adaptive lens assembly serves multiple functions: it adjusts optical power for different virtual object distances, maintains image quality across varying focal lengths, and works with a single waveguide structure. This multi-functionality replaces the need for multiple specialized waveguides, simplifying the overall system while preserving optical power variability.
3Reliability
If adaptive lens assembly with variable optical power is implemented, then accommodative and vergence states are aligned improving realism, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses liquid crystal variable focus lenses that can change their optical properties through electrical control rather than mechanical adjustment. This eliminates the need for precision mechanical interfaces and physical repositioning of lens elements, significantly reducing manufacturing precision requirements while maintaining reliable accommodation-vergence alignment through electronic control of focal length.
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 adaptive lens assembly enhances the realism and comfort of AR experiences by aligning accommodative and vergence states, reducing computational power requirements and minimizing the need for multiple waveguides.
Implementation Method 1
a birefringent lens and an isotropic lens contacting each other to form a conformal interface therebetween. The lens stack is configured to exert polarization-dependent optical power to linearly polarized light
Implementation Method 2
The adaptive lens assembly is configured to be selectively switched between a plurality of states having different optical powers to modify wavefront divergence
Data Source
AI summary
The present disclosure relates to display systems and, more particularly, to augmented reality display systems an related methods. In one aspect, an adaptive lens assembly includes a lens stack configured to exert polarization-dependent optical power to linearly polarized light. The lens stack includes a birefringent lens and an isotropic lens contacting each other to form a conformal interface therebetween. The adaptive lens assembly is configured to be selectively switched between a plurality of states having different optical powers.