Pupil-Aware Eye Tracking with Local Dimming for Retina Safety
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Solution Overview
Problem
Current eye tracking sensors in virtual and augmented reality systems project light uniformly onto the eye, posing a risk of retina damage and compromising tracking accuracy due to insufficient signal-to-noise ratio.
Innovation Solution
Implement pupil-aware eye tracking by locally dimming the projection or illumination corresponding to the pupil, reducing light entry through the pupil and increasing light intensity to non-pupil areas for enhanced safety and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light is projected uniformly onto the eye for eye tracking, then tracking signal strength is improved, but retina damage risk increases
Solution Approach 1:
The patent applies local quality by differentiating light intensity across different regions of the eye. Specifically, the pupil region receives reduced or blocked light intensity while the sclera and other non-pupil regions maintain or receive enhanced light intensity. This spatial variation in light quality enables safe eye tracking by preventing harmful light exposure to the retina through the pupil while preserving sufficient signal strength from reflective surfaces for accurate tracking measurements.
2Measurement precision
If light intensity to non-pupil areas is increased for better signal-to-noise ratio, then tracking accuracy is improved, but overall light exposure increases
Solution Approach 1:
The system applies local quality by selectively enhancing light intensity only in non-pupil regions such as the sclera, while simultaneously reducing or blocking light in the pupil region. This creates a spatially differentiated illumination pattern that optimizes the signal-to-noise ratio for tracking accuracy without proportionally increasing overall light exposure to the eye, thereby managing total energy delivery while improving measurement precision.
Solution Approach 2:
The patent segments the eye surface into functionally distinct regions: the pupil region (which requires light reduction for safety) and the non-pupil regions such as the sclera (which benefit from enhanced illumination for signal strength). By segmenting the illumination strategy by anatomical region, the system can independently optimize light intensity for each zone, improving tracking accuracy through enhanced scleral reflection while preventing harmful exposure through the pupil.
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
Reduces the risk of retina damage and improves eye tracking accuracy by minimizing light exposure through the pupil while enhancing the signal-to-noise ratio.
Implementation Method 1
project light uniformly onto the eye...project light...capturing an image of the eye...reflected light
Data Source
AI summary
Eye safety and eye tracking accuracy is enhanced through pupil-aware eye tracking, where a fringe pattern projection or illumination onto the eye is locally dimmed in an area corresponding to the pupil. Fringe projection local dimming is accomplished by modifying (locally dimming) the fringe pattern at the projector. Illumination local dimming is accomplished at the light source (e.g., a laser source) before the light is provided by a micro-electromechanical system (MEMS) to the eye. An amount of light provided to non-pupil areas such as sclera may be increased to enhance a signal-to-noise ratio (SNR), which may lead to more accurate eye tracking.