AR Display 3D Lightfield Optics for Accommodation-Convergence Discrepancy
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Solution Overview
Problem
Current augmented reality (AR) displays, particularly optical see-through head-mounted displays (OST-HMDs), suffer from visual discomfort due to accommodation-convergence discrepancy, where the eye struggles to focus on both digital information and real-world objects simultaneously, leading to issues like distorted depth perception and fatigue.
Innovation Solution
The integration of 3D lightfield creation technology and freeform optical technology in OST-HMDs, using micro-integral imaging (micro-InI) optics to reconstruct a 3D scene, allowing for correct focus cues across a large depth range and enabling a compact, lightweight design that maintains see-through capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional 2D display technology is used in AR displays, then the device can be compact and lightweight, but visual discomfort occurs due to accommodation-convergence discrepancy
Solution Approach 1:
The patent transitions from 2D display technology to 3D integral imaging technology, adding the depth dimension to the display. This allows the creation of a lightfield with varying focal depths, enabling the eyes to accommodate at different distances while maintaining convergence on the virtual image, thereby resolving the accommodation-convergence discrepancy and improving visual comfort without significantly increasing device weight.
Solution Approach 2:
The patent changes the optical parameters of the display by using integral imaging optics to create a lightfield with multiple focal planes. This allows dynamic adjustment of the focal depth parameter, enabling the display to match the accommodation distance of the user's eyes, thus eliminating visual discomfort while keeping the device compact.
2Ease of operation
If 3D integral imaging optics are integrated into AR displays, then visual comfort is improved by providing accurate focus cues, but device complexity increases
Solution Approach 1:
The patent merges the AR display optics with integral imaging optics into a unified optical system. By combining these functions, the patent avoids the need for separate complex subsystems, reducing overall device complexity while still providing the benefits of 3D lightfield display for improved visual comfort.
Solution Approach 2:
The optical system in the patent serves multiple functions: it acts as both the AR display optics and the integral imaging optics. This multi-functionality reduces the number of separate components needed, thereby simplifying the overall device structure while maintaining the capability to provide accurate focus cues for visual comfort.
3Adaptability or versatility
If traditional HMD optics are used, then see-through capability is maintained, but accommodation-convergence discrepancy causes visual fatigue
Solution Approach 1:
The patent enhances traditional see-through HMD optics by integrating 3D integral imaging capabilities, adding the depth dimension to the optical path. This allows the system to maintain see-through capability while providing varying focal planes that match the user's accommodation distance, eliminating the accommodation-convergence discrepancy and reducing visual fatigue.
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 approach significantly reduces visual discomfort and fatigue by providing accurate focus cues for digital information across varying distances, enhancing the usability of AR displays in applications requiring extended use.
Implementation Method 1
display optics configured to receive optical radiation from the microdisplay and configured to create a 3D lightfield
Implementation Method 2
microlens array (MLA) according to a prior art of the invention
Implementation Method 3
An eyepiece in optical communication with the display optics may also be included, with the eyepiece configured to receive the 3D lightfield from the display optics and deliver the received radiation to an exit pupil of the system
Data Source
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Figure 1C
AI summary
A 3D augmented reality display, comprising: a microdisplay for providing a virtual 3D image for display to a user; variable focus display optics configured to receive optical radiation from the microdisplay and configured to create a 3D lightfield from the received radiation at a location that may be varied by the variable focus optics; and an eyepiece in optical communication with the display optics configured to receive the 3D lightfield from the display optics and deliver the received radiation to an exit pupil of the augmented reality display. A related method is also described.