Smart Glasses Eye Tracking via Laser Feedback Interferometry
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Solution Overview
Problem
Existing eye-tracking systems for smart glasses are complex, energy-intensive, and have limited temporal resolution, making them inefficient and costly.
Innovation Solution
A method using wavelength-modulated laser beams for eye movement detection via laser feedback interferometry, which determines optical path length and Doppler shift to calculate eye velocity, allowing for efficient operation of input and output units based on eye movement, without the need for computationally intensive image processing or moving components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If camera-based systems or electrical sensors are used for eye tracking, then eye position can be detected, but the system complexity and energy consumption increase
Solution Approach 1:
The patent replaces mechanical camera-based systems and electrical sensors with an optical measurement system using laser feedback interferometry. A laser beam is directed at the eye, and the backscattered light is analyzed to detect eye position and velocity, eliminating the need for complex mechanical or electrical sensing components.
Solution Approach 2:
The patent introduces laser light as an intermediary medium between the eye-tracking system and the eye. The laser beam serves as a probe that interacts with the eye's optical properties, allowing non-contact measurement of eye position and velocity through optical interference patterns without requiring direct physical sensors on or near the eye.
2Measurement precision
If camera-based systems or electrical sensors are used for eye tracking, then eye position can be detected, but energy consumption increases
Solution Approach 1:
The patent replaces energy-intensive camera-based systems and electrical sensors with a low-power optical interferometry system. The laser feedback interferometry method requires minimal energy to generate and detect optical interference patterns, significantly reducing the power consumption of the eye-tracking function.
3Measurement precision
If conventional eye-tracking systems are used, then eye position can be determined, but temporal resolution is limited
Solution Approach 1:
The patent employs wavelength modulation of the laser beam at high frequencies to enable rapid sampling of eye position. By periodically modulating the laser wavelength and analyzing the resulting interference patterns, the system achieves high temporal resolution in tracking eye movements without sacrificing measurement precision.
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 enables high-resolution, energy-efficient eye movement detection with low component and energy requirements, allowing for flexible and robust operation of smart glasses with reduced power consumption and improved user convenience.
Implementation Method 1
detecting an optical path length of the emitted laser beam based on laser feedback interferometry of the emitted laser beam and radiation backscattered from the eye
Implementation Method 2
detecting a Doppler shift, in particular between frequencies, of the emitted and the backscattered radiation based on laser feedback interferometry
Data Source
AI summary
A method for operating smart glasses includes an input unit and/or output unit and a gaze detection arrangement, wherein the gaze detection arrangement detects any eye movement of an eye including the steps of irradiating at least one wavelength-modulated laser beam to the eye, detecting an optical path length of the emitted laser beam based on laser feedback interferometry of the emitted laser radiation with backscattered radiation from the eye, detecting a Doppler shift of the emitted and backscattered radiation based on the laser feedback interferometry, and detecting an eye velocity based on the Doppler shift, and wherein the input unit and/or output unit is operated based on the optical path length and/or the eye velocity.