Capacitance-Based Eye Tracker for Portable Clinical Diagnostics
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Solution Overview
Problem
Current eye-tracking technologies are inadequate for accurate, non-invasive, and portable measurement of eye movement, particularly in clinical settings, due to their bulkiness, invasiveness, and insufficient sensitivity, which can lead to inaccurate diagnoses of neurological disorders.
Innovation Solution
A wearable eye-tracking system utilizing carbon nanotube-paper composite capacitive sensors, integrated into eyeglasses or other headgear, measures eye movements by sensing the position of the eyelid and eyeball through vertical and horizontal capacitance sensors, providing real-time data with high sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a camera-based desktop eye-tracking system is used, then eye movement tracking capability is provided, but the system becomes bulky and not portable
Solution Approach 1:
The patent replaces the mechanical camera-based optical tracking system with a capacitive sensing system that uses electrical fields to detect eye movements. The capacitive sensors mounted on eyeglasses measure changes in capacitance caused by eye movements, eliminating the need for bulky cameras and complex optical mechanisms while maintaining tracking capability and enabling portability.
Solution Approach 2:
The patent changes the measurement parameter from optical reflection/corneal geometry (camera-based) to electrical capacitance (capacitive sensors). This parameter change enables miniaturization of the sensing system, allowing integration into lightweight eyeglasses while providing continuous real-time eye movement data without the bulk of desktop camera systems.
2Measurement precision
If conventional eye trackers are used in clinical settings, then eye movement measurement is provided, but setup time becomes long and equipment availability is low
Solution Approach 1:
The capacitive eye-tracking system is designed to be easily wearable and immediately functional, requiring minimal setup. The sensors are integrated into eyeglasses that patients can put on themselves, and the system begins recording eye movements automatically, eliminating the need for complex calibration procedures and lengthy setup times associated with conventional eye trackers.
Solution Approach 2:
The patent creates a universal eye-tracking platform that can be used across multiple clinical settings and with different patient populations. The wearable capacitive sensors work in various environments (clinics, laboratories, home settings) and can track different types of eye movements, making the equipment broadly applicable and eliminating the need for specialized, location-specific equipment.
3Object-affected harmful factors
If capacitive sensors are used for eye gaze detection, then measurement is non-invasive, but sensitivity is insufficient for precise measurement
Solution Approach 1:
The patent employs composite sensor structures combining conductive materials with flexible substrates to create highly sensitive capacitive sensors. These composite materials enhance the sensors' ability to detect minute changes in capacitance caused by eye movements while maintaining the non-invasive, wearable nature of the measurement system.
Solution Approach 2:
The patent optimizes the local properties of the capacitive sensors by positioning them in specific locations on the eyeglasses where they can most effectively detect eye movements. The sensors are configured with specific electrode geometries and arrangements that maximize sensitivity to corneal position changes while maintaining comfort and non-invasiveness.
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
The system enables precise, real-time tracking of eye movements without hindering vision, improving diagnostic accuracy and suitability for clinical use, while being portable and user-friendly.
Implementation Method 1
The movement of the eyeballs, muscles, and eyelids induce a change in the capacitance of a capacitor placed at a fixed point near the eye
Data Source
AI summary
An eye-tracking system, including at least one vertical capacitance sensor, configured to measure the vertical position of a cornea of a user's eye by sensing a position of an eyelid of the user; and at least one horizontal capacitance sensor, configured to measure the horizontal position of the cornea of the user's eye by sensing a position of the user's eyeball.