Adaptive Waveplate Lens Assembly for AR Depth Accommodation
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Solution Overview
Problem
Existing augmented reality (AR) technologies face challenges in providing a comfortable and natural presentation of virtual image elements amidst real-world imagery due to the complexity of the human visual system, leading to discomfort and mismatched accommodative and vergence states.
Innovation Solution
A display device incorporating a waveguide and a broadband adaptive lens assembly with switchable waveplate lenses that alter polarization and optical power, allowing for variable optical effects to enhance the presentation of virtual content at different depth planes while maintaining a realistic and comfortable viewing experience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional AR display systems are used, then virtual image elements can be presented, but the human visual system experiences discomfort and mismatched accommodative and vergence states
Solution Approach 1:
The patent implements dynamic optical power adjustment through liquid crystal lenses that can change their focal length in real-time. The optical system transitions from static to dynamic, allowing the accommodative state to match the vergence state by adjusting lens power based on the depth plane of virtual content, thereby resolving the visual comfort issue while maintaining manageable system complexity through controlled adaptability
2Adaptability or versatility
If multiple lenses are used to provide different optical powers for different depth planes, then the AR display can accommodate various virtual depths, but the thickness and weight of the display system increase
Solution Approach 1:
The patent changes the optical parameter (focal length) of a single lens assembly using liquid crystal technology rather than physically swapping or stacking multiple lenses. By electrically controlling the refractive index of the liquid crystal material, the system achieves multiple optical power states (e.g., +20D, +10D, 0D) from one compact component, maintaining depth plane versatility while minimizing weight and thickness
3Adaptability or versatility
If multiple lenses are used to provide different optical powers for different depth planes, then the AR display can accommodate various virtual depths, but the device structure becomes more complex
Solution Approach 1:
The patent applies spatially varying birefringence within the liquid crystal lens structure, where different regions of the liquid crystal layer have different optical properties. This local variation in optical quality allows a single lens element to achieve multiple optical power states through polarization control, simplifying the overall lens assembly while maintaining the ability to accommodate various depth planes
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 provides a more natural and comfortable AR experience by aligning accommodative and vergence states, reducing the thickness and weight of the display system, and simplifying the driving mechanism through switchable waveplates.
Implementation Method 1
a waveguide configured to guide light in a lateral direction parallel to an output surface of the waveguide. The waveguide is further configured to outcouple the guided light through the output surface
Implementation Method 2
configured to diffract the outcoupled light at a diffraction efficiency greater than 90% within a wavelength range including at least 450 nm to 630 nm
Implementation Method 3
a first waveplate lens comprising a liquid crystal (LC) layer arranged such that the waveplate lens has birefringence (Δn) that varies in a radially outward direction from a central region of the first waveplate lens
Implementation Method 4
Each of the one or more switchable waveplates is configured to diffract the outcoupled light at a diffraction efficiency greater than 90% within a wavelength range including at least 450 nm to 630 nm and to selectively alter a polarization state of light passing therethrough
Data Source
AI summary
A display device comprises a waveguide configured to guide light in a lateral direction parallel to an output surface of the waveguide. The waveguide is further configured to outcouple the guided light through the output surface. The display device additionally comprises a broadband adaptive lens assembly configured to incouple and to diffract therethrough the outcoupled light from the waveguide. The broadband adaptive lens assembly comprises a first waveplate lens comprising a liquid crystal (LC) layer arranged such that the waveplate lens has birefringence (Δn) that varies in a radially outward direction from a central region of the first waveplate lens and configured to diffract the outcoupled light at a diffraction efficiency greater than 90% within a wavelength range including at least 450 nm to 630 nm. The broadband adaptive lens assembly is configured to be selectively switched between a plurality of states having different optical powers.