Waveguide Light Field Near-Eye Display for Vergence-Accommodation Relief
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Solution Overview
Problem
Waveguide-based augmented reality near-eye displays suffer from vergence-accommodation conflict due to a mismatch between the vergence angle and focus depth, leading to eye strain and visual fatigue, and existing solutions either obstruct the view or have overly complex structures.
Innovation Solution
A light field near-eye display assembly utilizing a MEMS scanning mirror and spatial light modulator to adjust the incident angle of illumination beams, combined with a waveguide assembly, to create a three-dimensional display effect by synchronizing the refresh rates of these components, reducing volume and optimizing structure complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a waveguide-based near-eye display is used, then the device achieves small volume and lightness, but the virtual image is always at infinity causing vergence-accommodation conflict and visual fatigue
Solution Approach 1:
The patent employs a tunable lens that can dynamically adjust its focal length to match different vergence angles. This dynamic focusing capability allows the virtual image distance to be adjusted, enabling the focal plane to coincide with the vergence plane and thereby resolving the vergence-accommodation conflict while maintaining the compact waveguide structure
Solution Approach 2:
The patent changes the optical parameter (focal length) of the lens system to achieve different virtual image distances. By adjusting the focal length parameter, the system can present virtual images at various depths, allowing the eye's accommodation to match the vergence angle and eliminate visual fatigue
2Adaptability or versatility
If a reflective spatial light modulator is placed on the optical axis, then light field display is achieved, but the view of the actual scene is obstructed
Solution Approach 1:
The patent moves the spatial light modulator from the optical axis to a lateral position, utilizing the lateral dimension for light field modulation. This dimensional relocation allows the modulator to function without blocking the direct optical path to the user's eye, eliminating scene view obstruction while preserving light field display capabilities
3Adaptability or versatility
If multiple components (lighting assembly array, waveguide, spatial light modulator, retinal projection) are integrated, then light field near-eye display is achieved, but the structure becomes overly complex
Solution Approach 1:
The patent combines the lighting assembly and spatial light modulator into a single integrated unit, reducing the number of separate components. This merging approach simplifies the overall structure while maintaining the light field display function, making the system more suitable for practical AR applications
Solution Approach 2:
The patent designs the waveguide to serve multiple functions: guiding light from the source, interacting with the spatial light modulator, and delivering the light field to the user's eye. This multi-functionality reduces the need for separate dedicated components, thereby simplifying the overall system structure
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 assembly achieves a true three-dimensional light field display, resolving the vergence-accommodation conflict and eliminating visual fatigue while maintaining a compact and lightweight design.
Implementation Method 1
The MEMS scanning mirror is provided on a projection side of the lighting assembly and configured to deflect the illumination beam projected by the lighting assembly to adjust an incident angle of the illumination beam
Implementation Method 2
an image source generated by a micro-projection optical machine enters a waveguide after passing through a collimating lens and a coupling-in device, is totally reflected in the waveguide to a coupling-out section
Implementation Method 3
is totally reflected in the waveguide to a coupling-out section, and is diffracted into human eyes through a coupling-out device
Data Source
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Figure 6A~6B
AI summary
A light field near-eye display assembly, a light field near-eye display apparatus, and a light field near-eye display method are provided. The light field near-eye display assembly includes: a lighting assembly, configured to project an illumination beam; an MEMS scanning mirror, provided on a projection side of the lighting assembly and configured to deflect the illumination beam projected by the lighting assembly to adjust an incident angle of the illumination beam; a waveguide assembly, including an optical waveguide, and a coupling-in device and a coupling-out device provided on the optical waveguide; and a spatial light modulator, having the same refresh rate as the MEMS scanning mirror and configured to modulate the illumination beam deflected by the MEMS scanning mirror into image light at a corresponding viewing angle to propagate to the coupling-in device.