AR Eye Tracking Layout With In-View IR Illumination
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Solution Overview
Problem
Existing augmented reality systems face challenges in improving eye tracking performance, particularly in accurately determining eye orientation metrics such as center of eye rotation, interpupillary distance, and gaze angle, due to the complexity of human visual perception and nervous system interactions with virtual and real-world imagery.
Innovation Solution
The system positions illumination sources closer to the optical axis than the periphery of the eyepiece output region, utilizing infrared light emitting diodes (IR LEDs) to illuminate the eye, and employs dedicated eye cameras positioned in front of the user's eyes to capture reflected light for eye tracking, combined with software algorithms to determine eye orientation metrics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If illumination sources are positioned outside the field of view, then the virtual content is not blocked, but eye tracking performance is degraded
Solution Approach 1:
The patent positions illumination sources within the field of view by utilizing the third dimension (depth) to place them at different axial distances from the eyepiece. This allows the illumination sources to be spatially separated from the virtual content plane, enabling them to illuminate the eye without blocking the virtual content path.
Solution Approach 2:
The patent applies different spatial positioning strategies to different components: illumination sources are placed at specific axial distances within the field of view optimized for eye tracking, while virtual content is rendered at different depth planes. This local optimization of positioning for different functional requirements resolves the contradiction between eye tracking effectiveness and virtual content visibility.
2Measurement precision
If illumination sources are positioned at multiple axial distances, then eye tracking accuracy is improved across demographics, but device complexity increases
Solution Approach 1:
The patent implements a multi-distance illumination source arrangement that provides more illumination paths than strictly necessary for basic eye tracking. This excessive action ensures robust eye tracking performance across diverse user demographics and eye positions, with the trade-off of increased device complexity being acceptable for achieving universal compatibility.
Solution Approach 2:
The multi-distance illumination source configuration serves multiple functions: it enables accurate eye tracking for various eye positions and orientations, accommodates different user demographics, and maintains performance across different gaze angles. This universal design approach justifies the increased device complexity by achieving broad applicability.
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
Enhances eye tracking performance by accurately determining eye orientation metrics, enabling a comfortable and natural presentation of virtual image elements within augmented reality environments.
Implementation Method 1
using a combination of infrared light emitting diodes (LEDs) and an optical element with optical power
Implementation Method 2
using a combination of infrared light emitting diodes (LEDs) and an optical element with optical power
Implementation Method 3
to capture images of the user's eye and determine eye orientation metrics
Data Source
AI summary
A wearable device for projecting image light to an eye of a viewer and forming an image of virtual content in an augmented reality display is provided. The wearable device includes a projector and stack of waveguides optically connected to the projector. The wearable device also includes an eye tracking system comprising a plurality of illumination sources, an optical element having optical power, and a set of cameras. The optical element is disposed between the plurality of illumination sources and the set of cameras. In some embodiments, the augmented reality display includes an eyepiece operable to output virtual content from an output region and a plurality of illumination sources. At least some of the plurality of illumination sources overlap with the output region.