Polarized NIR Retinal Gaze Tracking Without Moving Parts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current eye tracking systems are limited in accuracy as they detect eye position rather than actual visual axis or point of fixation, and often require moving parts or optics, making them costly and difficult to compactly integrate into portable devices.
Innovation Solution
An electronically scannable optical illumination system emitting polarized near-infrared light to the retina, combined with a polarization-sensitive optical detection system and signal processing, which uses a spatially closed loop scanning path to determine gaze direction and fixation without moving parts or additional optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If moving parts or additional optics are used to achieve accurate eye tracking, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces mechanical scanning systems with electronically controllable light sources that can be selectively activated to illuminate different retinal locations. This substitution eliminates moving parts while maintaining the ability to track eye gaze through polarization-sensitive detection of light reflected from retinal landmarks.
Solution Approach 2:
The patent utilizes changes in polarization state of light as it reflects from different retinal locations. By detecting polarization parameters rather than relying on mechanical position sensing, the system achieves accurate eye tracking without complex mechanical components. The polarization state serves as the key parameter for determining gaze direction.
2Measurement precision
If moving parts are incorporated into the eye tracking system, then measurement precision is improved, but reliability deteriorates
Solution Approach 1:
The patent eliminates mechanical moving parts by using electronically addressable light-emitting elements that can be controlled through software. This solid-state approach significantly improves reliability by removing components subject to mechanical wear, friction, and failure, while maintaining precise fixation detection through polarization-based retinal landmark tracking.
3Measurement precision
If additional optics are added to improve eye tracking accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex optical scanning systems with a solid-state light emitting array that can be electronically controlled to illuminate specific retinal locations. This approach maintains high measurement precision for gaze direction detection while dramatically reducing optical system complexity by eliminating the need for moving mirrors, lenses, and other mechanical optical components.
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 solution provides precise eye tracking and gaze fixation detection using retinal landmarks, offering improved accuracy and compact, portable designs for various applications, including computer interfaces and medical diagnostics.
Implementation Method 1
an optical detection system arranged in an optical path of the NIR light after being reflected from the retina of the eye of the subject, the optical detection system providing a detection signal
Implementation Method 2
measuring the amount of polarization change that the surrounding birefringent nerve fibers cause during double passage of a beam of polarized light through them upon fundus reflection in double-pass systems
Data Source
AI summary
An eye tracking and gaze fixation detection system, includes an electronically scannable optical illumination system emits polarized near-infrared (NIR) light to a retina in an eye of a subject; an optical detection system arranged in an optical path of the NIR light after being reflected from the retina of the eye of the subject, the optical detection system providing a detection signal; and a signal processing system communicates with the optical detection system to receive the detection signal, wherein the optical illumination system emits the polarized NIR light to illuminate at least a portion of a scanning path, wherein the scanning path is a spatially closed loop across a portion of the retina in the eye of the subject that repeats periodically over time, and wherein the signal processing system is configured to determine at least one of a gaze direction and a gaze fixation based on the detection signal.