Translatable Reflector Pancake Lens for Vergence-Accommodation Relief
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Solution Overview
Problem
Existing near-eye displays suffer from vergence-accommodation conflict due to limited capability in compensating for discrepancies between eye vergence and focusing, leading to visual fatigue and nausea.
Innovation Solution
A tunable lens system with translatable reflective elements, including a pancake lens design using polarization beam folding and actuators, dynamically adjusts the focal length and image plane to align with changing eye vergence, reducing reliance on physical movement of display panels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed focal length ocular lens is used in near-eye displays, then the device structure is simple and compact, but the vergence-accommodation conflict occurs causing visual fatigue
Solution Approach 1:
The patent applies the dynamics principle by making the ocular lens focal length adjustable rather than fixed. The lens system includes a tunable lens that can dynamically change its focal length to match the user's accommodation state, thereby resolving the vergence-accommodation conflict while maintaining adaptability without excessive complexity
Solution Approach 2:
The patent utilizes parameter changes by varying the focal length parameter of the ocular lens according to the user's viewing distance and accommodation needs. This allows the lens to adapt to different visual tasks and reduce visual fatigue while maintaining a relatively simple overall device structure
2Adaptability or versatility
If the display panel is physically moved to adjust focus, then the focal length adjustment is achieved, but the device becomes bulky and complex
Solution Approach 1:
The patent replaces the mechanical movement of the display panel with an optical solution. Instead of physically moving the display panel to adjust focus, the system uses a tunable lens that can change its focal length optically, eliminating the need for complex mechanical movement components and reducing device bulk
Solution Approach 2:
The patent introduces a tunable lens as an intermediary element between the display panel and the user's eye. This intermediary component handles the focal length adjustment function, allowing the display panel to remain stationary while still achieving focus adjustment through optical means rather than mechanical movement
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 effectively alleviates vergence-accommodation conflict by allowing rapid adjustment of the focal length and image plane, enhancing user comfort and reducing fatigue in near-eye displays.
Implementation Method 1
A tunable lens system with translatable reflective elements, including a pancake lens design using polarization beam folding
Implementation Method 2
The first reflector is configured to at least partially transmit a light beam therethrough to impinge onto the second reflector. The second reflector is configured to at least partially reflect the light beam propagated through the first reflector back to the first reflector.
Data Source
AI summary
A tunable lens including a pair of reflectors is disclosed. At least one of the reflectors may be curved for contributing to the focusing or defocusing power of the lens. At least one of the reflectors is translatable for tuning the focusing/defocusing power. The reflectors may be configured in a pancake lens configuration where one of the reflectors is a 50/50 reflector and the other is a polarization selective reflector. Refractive elements may be disposed between the reflectors for providing more optical power to the lens, and/or for balancing optical aberrations.