Freeform VR Optics With Addressable Focus for Vergence-Accommodation Conflict
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Solution Overview
Problem
Conventional stereoscopic displays suffer from accommodation-convergence conflict by decoupling accommodation cues from convergence cues and tying them to a fixed distance, which limits the effectiveness of virtual and augmented reality systems.
Innovation Solution
A freeform optical system with addressable focus is employed to generate stereoscopic images, utilizing primary and secondary freeform optical elements in a tiled arrangement, along with a variable focusing system to adjust focal distances and address both accommodation and convergence cues independently, thereby resolving the accommodation-convergence conflict.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional stereoscopic displays decouple accommodation cues from convergence cues and tie them to a fixed distance, then device complexity is reduced, but visual comfort and realism deteriorate due to accommodation-convergence conflict
Solution Approach 1:
The patent implements dynamic focus adjustment by varying the optical power of the optical system in response to detected eye fixation points. The optical power changes dynamically to shift focal planes, allowing the system to accommodate different viewing distances and depths while maintaining visual comfort. This dynamic adjustment resolves the accommodation-convergence conflict by enabling the focal plane to move independently from the fixed display surface.
Solution Approach 2:
The system changes optical parameters (optical power, focal length) based on detected eye fixation points. By varying these parameters dynamically, the system can present content at different virtual depths and distances, allowing accommodation cues to match convergence cues and eliminating the visual discomfort caused by fixed-focus stereoscopic displays.
2Manufacturing precision
If a fixed focal distance is used in stereoscopic displays, then manufacturing precision requirements are reduced, but image quality and visual realism deteriorate due to inability to address multiple depths
Solution Approach 1:
The patent employs dynamic focus adjustment by varying the optical power of the optical system in response to detected eye fixation points. This allows the system to shift focal planes dynamically, presenting content at different virtual depths and distances. The dynamic nature of the system enables high precision focus control adaptable to different viewing conditions, overcoming the limitations of fixed focal distance systems.
Solution Approach 2:
The system uses eye fixation point detection as feedback to adjust the optical power of the system. This closed-loop control enables the system to automatically adapt to the user's viewing behavior, maintaining high image quality and visual realism by ensuring the focal plane is always appropriately positioned relative to the user's point of interest.
3Adaptability or versatility
If the field of view is expanded in head-mounted displays, then adaptability and user experience improve, but device complexity and optical system challenges increase
Solution Approach 1:
The patent divides the optical system into multiple independent optical channels, each serving a specific field of view region. This segmentation allows each optical element to be optimized for its specific function while collectively providing an expanded overall field of view. The modular segmented approach manages complexity by breaking down the challenging task of wide-FOV optics into more manageable regional optical paths.
Solution Approach 2:
The optical system is designed with multi-functional optical elements that can serve multiple purposes: providing wide field of view, enabling dynamic focus adjustment, and supporting stereoscopic depth perception. By making optical components universal and multi-functional, the system achieves expanded adaptability without proportionally increasing overall device complexity.
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 provides an expanded field of view and accurate focus control, enhancing the realism and comfort of virtual and augmented reality experiences by aligning accommodation and convergence cues dynamically, improving image quality and user experience.
Implementation Method 1
one or more refractive surfaces and one or more reflective surfaces to allow the injected light rays to deflect or reflect
Implementation Method 2
one or more refractive surfaces and one or more reflective surfaces to allow the injected light rays to deflect or reflect
Implementation Method 3
a variable focusing system to change a focal distance of a focal plane onto which at least a portion of the virtual display content will be rendered in focus
Data Source
AI summary
Several unique hardware configurations and methods for freeform optical display systems are disclosed. A freeform display system includes primary freeform optical element(s) and secondary freeform optical element(s) in tiled arrangements to expand the horizontal field of view (FOV) or the vertical field of view. The system may include a variable focusing system that produces intermediate pupil and changes the focal distance of a single focal plane or switches among multiple focal planes for rendering objects in focus while resolving accommodation-convergence conflict. The system may map light samples to appropriate light rays in physical space and use a cluster of projectors to project the mapped light rays to produce the light field of the virtual display content. Methods for making tiled freeform optical display systems and methods for producing virtual content with variable focus freeform optics and rendering light fields are also disclosed.