Transmissive Beamsplitter AR Optics for Vergence-Accommodation Matching
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Solution Overview
Problem
Conventional virtual and augmented reality systems fail to provide a comfortable, natural-feeling, rich presentation of virtual image elements amidst real-world imagery due to mismatches in vergence and accommodation, obstructed views, and inadequate consideration of human visual perception mechanisms, leading to user discomfort and fatigue.
Innovation Solution
The system employs a transmissive beamsplitter substrate with switchable reflective surfaces and variable focus lenses to present image information in a frame-sequential manner, utilizing electro-active materials like lithium niobate and MEMS devices to create a larger field of view and accommodate varying focal distances, integrating head and eye motion cues for enhanced user comfort and three-dimensional perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If stereoscopic wearable glasses with two displays are used to provide three-dimensional perception, then three-dimensional perception is improved, but user comfort deteriorates due to vergence-accommodation mismatch
Solution Approach 1:
The patent implements dynamic focus adjustment by varying the optical power of the display system over time to match the vergence demands of stereoscopic content. The optical power is adjusted in sync with the presented visual stimuli, allowing the accommodation system to remain in sync with vergence, thereby resolving the vergence-accommodation mismatch while maintaining three-dimensional perception.
Solution Approach 2:
The system employs periodic modulation of optical power that corresponds to the frame rate and stereoscopic presentation rhythm. By synchronizing optical power variations with the periodic presentation of left and right eye images, the system creates natural accommodation cycles that match vergence cycles, eliminating discomfort while preserving depth perception.
2Loss of information
If conventional AR displays are used to present virtual content, then virtual content presentation is achieved, but field of view is obstructed and visual comfort is reduced
Solution Approach 1:
The patent utilizes the time dimension by presenting different focal plane information in different time frames. By rapidly alternating between different optical power settings corresponding to different depths, the system creates a temporal multiplexing effect where the user perceives multiple focal planes without spatial obstruction, effectively adding a temporal dimension to the display architecture.
Solution Approach 2:
The system dynamically changes the optical power parameter of the display system to present content at different focal distances. By modulating optical power in response to the depth information of virtual content, the system can present both near and far virtual objects without physical obstructions, maintaining a clear view of the real world while enriching the virtual content presentation.
3Device complexity
If static focus displays are used, then device simplicity is maintained, but visual comfort deteriorates due to lack of accommodation freedom
Solution Approach 1:
The patent replaces mechanical focus adjustment mechanisms with electro-optic or liquid crystal-based optical power modulation. This substitution allows for rapid, precise, and programmable control of focus without complex mechanical moving parts, maintaining relative system simplicity while enabling dynamic accommodation that matches vergence demands for enhanced visual comfort.
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 enables a high-quality, comfortably perceived augmented reality experience with improved three-dimensional perception and reduced eye strain by aligning with human visual physiology, allowing for dynamic focus adjustment and seamless integration of virtual content with the real world.
Implementation Method 1
providing one or more light patterns associated with one or more frames of image data in a time-sequential manner from an image-generating source that oscillates or vibrates
Implementation Method 2
utilizing electro-active materials like lithium niobate and MEMS devices to create a larger field of view
Implementation Method 3
The substrate comprises a plurality of reflectors housed in the substrate
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
The invention relates to a method for displaying virtual content to a user, the method comprising: providing one or more light patterns associated with one or more frames of image data in a time-sequential manner; reflecting the one or more light patterns associated with the one or more frames of image data via a transmissive beamsplitter to an exit pupil, the transmissive beamsplitter having a plurality of reflectors to variably direct light toward the exit pupil.