Segmented Phase Profile Liquid Crystal Lenses for Vergence-Accommodation Conflict
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Solution Overview
Problem
Existing virtual reality and augmented reality headsets often cause visual fatigue and nausea due to the inability to correctly render vergence and accommodation conflicts, leading to a discrepancy between the vergence distance and accommodative distance for users.
Innovation Solution
An optical system comprising an electronic display, an adaptive lens assembly with adjustable liquid crystal (LC) lenses, and an eye tracking device, where the LC lenses are activated individually based on eye tracking information to dynamically adjust the focal length and reduce the vergence-accommodation conflict.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single focal length lens is used in existing headsets, then the device structure is simple, but the vergence-accommodation conflict cannot be resolved causing visual fatigue and nausea
Solution Approach 1:
The patent divides the lens into multiple adjustable liquid crystal lenses arranged in an array, where each lens can be independently controlled to provide different focal lengths. This segmentation allows the system to resolve vergence-accommodation conflict by selecting appropriate focal lengths while maintaining a manageable structure through modular design.
Solution Approach 2:
The patent implements dynamic focal length adjustment by using adjustable liquid crystal lenses that can change their optical power in real-time based on eye tracking information. This dynamic capability enables the system to adapt to varying accommodation requirements without requiring multiple fixed lenses, balancing adaptability with structural simplicity.
2Adaptability or versatility
If multiple adjustable LC lenses are arranged in an array, then the vergence-accommodation conflict is resolved, but the device complexity increases
Solution Approach 1:
The patent makes each liquid crystal lens in the array independently controllable and functionally equivalent, allowing any lens to serve multiple purposes depending on activation. This universality reduces the need for specialized components and simplifies the control system by using a standardized interface for all lenses in the array.
Solution Approach 2:
The system uses eye tracking information to automatically determine which lenses to activate and how to configure them, eliminating the need for manual intervention or complex external control mechanisms. The lenses self-organize their activation pattern based on the detected eye position and vergence requirements.
3Speed
If SPP LC lenses are stacked together to reduce response time, then the lens response speed improves, but the manufacturing complexity increases
Solution Approach 1:
The patent stacks multiple segmented phase profile LC lenses within each other in a compact arrangement, where smaller lenses are positioned within the optical path of larger lenses. This nested configuration achieves rapid response times by reducing the total LC material thickness while maintaining the optical functionality through precise alignment of the stacked components.
Solution Approach 2:
The patent transitions from a planar single-layer lens design to a three-dimensional stacked arrangement of multiple LC lens layers. This dimensional change allows the system to achieve faster response times by reducing the optical path length through the LC material while maintaining the segmented phase profile functionality across multiple layers.
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 effectively addresses the vergence-accommodation conflict by ensuring that the focal length of the lenses matches the vergence distance, reducing user fatigue and nausea by providing a more comfortable viewing experience.
Implementation Method 1
Each SPP LC lens may include a plurality of ring electrodes corresponding to the concentric rings; the ring electrodes may be concentric with an identical area; and a phase difference between adjacent electrodes may be the same, such that the phase profile is a parabolic phase profile.
Implementation Method 2
Each SPP LC lens may be a refractive Fresnel LC lens including a plurality of concentric rings of increasing radii to create a phase profile for the SPP LC lens.
Implementation Method 3
Each adjustable LC lens includes a plurality of segmented phase profile (SPP) LC lenses stacked together to reduce response time of the adjustable LC lens
Implementation Method 4
a phase difference between adjacent electrodes may be the same, such that the phase profile is a parabolic phase profile
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3~4A
AI summary
An optical system is provided. The optical system includes an electronic display, an adaptive lens assembly, and an eye tracking device. The electronic display displays a virtual scene for a user of the optical system; the adaptive lens assembly is optically coupled to the electronic display between the electronic display and eyes of the user; and the eye tracking device provides eye tracking information of the eyes of the user. The adaptive lens assembly includes a plurality of adjustable liquid crystal (LC) lenses arranged in an array, and the adjustable LC lenses are activated individually based on the eye tracking information.