Variable Focus AR Waveguide Lenses for Vergence-Based Vision Correction
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Solution Overview
Problem
Existing augmented reality (AR) technologies struggle to provide a comfortable and natural-feeling presentation of virtual image elements amidst real-world imagery due to refractive errors and fixed optical power issues, causing aberrations and discomfort for users with varying vision needs.
Innovation Solution
A display system with first and second variable focus lens elements positioned on either side of a waveguide, configured to correct refractive errors and provide adaptable optical power for both virtual and real-world objects, utilizing an eye tracking system to determine vergence and adjust corrections accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed optical power lens elements are used in AR displays, then the device structure is simple, but users with varying vision needs experience aberrations and discomfort
Solution Approach 1:
The patent applies variable focus lens elements that can dynamically adjust their optical power to correct refractive errors for different users. The lens elements transition between different focal states to provide customized optical correction while maintaining a single integrated device structure, resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The optical power parameter of the lens elements is made variable rather than fixed. By changing the focal length parameter dynamically, the system can accommodate users with different vision requirements (myopia, hyperopia, presbyopia) without requiring multiple different physical lenses, thus improving adaptability without proportionally increasing complexity.
2Ease of operation
If variable focus lens elements are added to correct refractive errors, then optical comfort is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The variable focus lens elements serve multiple functions: they correct refractive errors for different types of vision impairment (myopia, hyperopia, presbyopia), adjust focal depth for virtual images, and maintain optical quality across different user populations. This multi-functionality in a single component reduces the need for multiple specialized lenses, improving ease of manufacture relative to the comfort benefits.
Solution Approach 2:
The patent uses waveguide technology to create virtual images that can be focused at different depths. The variable focus lens elements work in conjunction with the waveguide's optical field to provide correction, allowing the system to replicate the effect of multiple different prescription lenses through a single adaptable optical path.
3Measurement precision
If multiple lens elements are used to provide comprehensive corrections, then correction accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple correction functions into a single variable focus lens element. Rather than using separate lenses for different correction types (myopia correction, hyperopia correction, presbyopia correction), the system merges these functions into one adaptable optical component that can be tuned to provide the appropriate correction for each user's specific vision needs, maintaining correction accuracy while reducing element count.
Solution Approach 2:
The variable focus capability allows a single lens element to dynamically assume different optical powers corresponding to different correction requirements. This dynamic adjustment replaces what would traditionally require multiple static lenses, achieving comprehensive correction accuracy without proportionally increasing 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
Enables users to view both real and virtual objects with high optical image quality, providing comfort and clarity across different distances without the need for physical lens changes, and allowing a wider range of corrections than conventional glasses, enhancing user experience and simplifying manufacturing.
Implementation Method 1
first variable focus lens element between the waveguide and an eye of the user... configured to adjust a wavefront of light projected from the waveguide
Implementation Method 2
correct refractive errors and provide adaptable optical power for both virtual and real-world objects
Data Source
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AI summary
An augmented reality display system includes a pair of variable focus lens elements that sandwich a waveguide stack. One of the lens elements is positioned between the waveguide stack and a user's eye to correct for refractive errors in the focusing of light projected from the waveguide stack to that eye. The lens elements may also be configured to provide appropriate optical power to place displayed virtual content on a desired depth plane. The other lens element is between the ambient environment and the waveguide stack, and is configured to provide optical power to compensate for aberrations in the transmission of ambient light through the waveguide stack and the lens element closest to the eye. In addition, an eye-tracking system monitors the vergence of the user's eyes and automatically and continuously adjusts the optical powers of the pair of lens elements based on the determined vergence of those eyes.