AR Optical Engine Polarization Routing for Vergence-Accommodation Conflict
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Solution Overview
Problem
Augmented reality (AR) systems face challenges with visual fatigue due to the mismatch between synthetic and real-world images, leading to vergence-accommodation conflict (VAC), and existing AR headsets are bulky due to the need for multiple components, which does not effectively address VAC and may reduce optical power.
Innovation Solution
The optical system splits unpolarized light into differently polarized beams, routing them through separate light paths to different observation planes using a combination of polarizing beam splitters, quarter wave plates, and reflective elements, allowing for recombination and maximizing optical power while reducing system size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the size of AR system is increased to improve vergence-accommodation conflict, then the VAC may be improved, but the optical power of existing components is reduced and the device becomes bulkier
Solution Approach 1:
The optical system segments the light path into multiple distinct paths (first light path and second light path) that traverse different physical distances. This segmentation allows each path to be optimized independently, with the first path being longer to provide better accommodation for near viewing while the second path is shorter, thereby resolving the VAC issue without requiring a uniform increase in overall system size that would reduce optical power.
2Adaptability or versatility
If multiple components are accommodated in AR headset to generate AR image, then the AR image generation capability is achieved, but the headset becomes bulky and large in size
Solution Approach 1:
The optical system merges multiple optical functions into a unified architecture where a single display device serves both near-eye viewing and far-field viewing through the polarized light path separation. The beam splitter and wave plates are integrated into a compact arrangement that combines accommodation control, polarization manipulation, and light routing functions, reducing the overall headset volume while maintaining full AR image generation capability.
3Volume of moving object
If a single display is used to project synthetic images, then the system size is reduced, but the apparent resolution and optical power are maximized through specific optical configurations
Solution Approach 1:
The system changes the polarization state parameter of light as it traverses different paths. By using quarter-wave plates to convert linearly polarized light to circularly polarized light and back, the system creates distinct optical paths from a single display source. This parameter change enables the single display to effectively project images with high apparent resolution by utilizing polarization multiplexing, thereby maintaining system compactness while achieving superior resolution performance.
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
This configuration enhances user comfort by projecting realistic synthetic images with high apparent resolution from a single small display, reducing the size and increasing efficiency of the AR system while minimizing the need for brighter displays.
Implementation Method 1
splits unpolarized light into differently polarized beams
Implementation Method 2
route the components of oppositely polarized light corresponding to a single image to different light paths
Implementation Method 3
routing them through separate light paths to different observation planes using a combination of polarizing beam splitters, quarter wave plates, and reflective elements
Data Source
AI summary
Optical display engines with reduced size and/or increased efficiency for Augmented Reality (AR) and near-eye devices that incorporate LED, microLED, and/or OLED displays. Example optical systems provide different light paths for polarized (or split unpolarized) light, with recombining oppositely polarized light corresponding to different image portions/channels, in a compact system using polarized beam splitters, quarter wave plates, half wave plates, and reflective elements such as curved mirrors or reflective lenses, resulting in high optical power. Images and/or portions thereof are presented at multiple observation planes to project a more realistic synthetic image, and at different angular resolutions to enable creation of a large composite field of view with high apparent resolution from a single small and efficient display.