Resonant MEMS Scanner Eye-Tracker for Low Latency
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Solution Overview
Problem
Conventional eye-tracking systems are slow, bulky, invasive, and expensive, with significant lag between eye movement and measured eye position, making them unsuitable for many applications, including VR, due to their reliance on cameras and image processing software.
Innovation Solution
An eye-tracking system using a two-axis resonant MEMS scanner that scans a light signal in a Lissajous pattern over the eye region, driven by periodic signals near the resonant frequencies of each axis, enabling high-density scanning with low temporal latency and high spatial resolution without the need for imaging processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional eye-trackers use cameras and image processing software, then they can track eye movement, but they become slow, bulky, expensive, and power hungry with significant lag
Solution Approach 1:
The patent extracts and eliminates the camera and image processing software components from the eye-tracking system. Instead of using complex imaging systems, the invention employs a light source, scanner, and photodetector configuration that directly measures eye position through optical reflections, removing the bulky and computationally intensive imaging subsystems while maintaining tracking functionality
Solution Approach 2:
The patent replaces the mechanical/optical imaging system (camera) with a non-imaging photodetector system that uses light scattering and reflection principles. The system substitutes complex image processing algorithms with direct optical measurement of eye position based on reflected light patterns, achieving faster response times and reduced computational requirements
2Measurement precision
If conventional eye-trackers use cameras and image processing, then they can measure eye position, but they become expensive and power hungry
Solution Approach 1:
The patent removes the power-intensive camera and image processing software from the system. The replacement photodetector-based optical measurement system consumes significantly less power while maintaining the ability to accurately track eye position through direct optical sensing rather than computational image analysis
Solution Approach 2:
The patent employs simpler, lower-cost optical components (light source, scanner, photodetector) instead of expensive camera systems. The system uses readily available optical elements and straightforward detection methods that reduce overall system cost and power requirements while achieving the necessary measurement precision
3Measurement precision
If conventional eye-trackers use cameras, then they can track eye movement, but they become bulky and invasive
Solution Approach 1:
The patent extracts and eliminates the bulky camera subsystem from the eye-tracking device. The remaining components (light source, scanner, photodetector) form a compact configuration that can be integrated into lightweight form factors suitable for wearable applications, while the non-imaging photodetector system maintains accurate eye position measurement without requiring heavy imaging hardware
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 allows for precise, rapid eye tracking with low latency and reduced system size and cost, enhancing user mobility and experience in applications like VR and human-computer interaction.
Implementation Method 1
a two-axis, resonant MEMS scanner that scans a light signal in a Lissajous pattern over the eye region, driven by periodic signals near the resonant frequencies of each axis
Implementation Method 2
scanning a light signal in a Lissajous pattern that precesses at a high rate using a two-axis, resonant MEMS scanner
Implementation Method 3
tracks the motion of the eye by detecting one or more reflections from the eye
Data Source
AI summary
The present disclosure describes systems and methods that enable eye-tracking by steering a light signal in a high-density Lissajous pattern over a region of an eye and detecting light reflected from the eye using a non-imaging photodetector configuration. The light signal is scanned by driving each axis of a two-axis MEMS scanner with a periodic signal having a frequency that is based on the resonant frequency of that axis. By choosing periodic signals having frequencies that give rise to precession of the Lissajous pattern at a high rate, a high-density scan pattern is quickly generated, thereby enabling eye tracking with high spatial resolution and low latency.