Eye Tracking System Using Laser Scanning Mirror
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 virtual reality and wearable technology, due to their reliance on cameras and image processing, which also restricts user mobility and increases system cost.
Innovation Solution
An eye-tracking system mounted on eyeglass frames using a laser, two-dimensional scanning mirror, and discrete detector, which sweeps an optical input signal over the eye to estimate the corneal vector without the need for image sensors or complex image processing, allowing for high-resolution, low-power, and fast tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional eye-tracking systems use cameras and image processing, then measurement capability is achieved, but system speed and responsiveness deteriorate due to significant lag between eye movement and measured eye position
Solution Approach 1:
The patent replaces the mechanical/optical imaging system (cameras and image processing software) with an electro-optical detection system using a photodetector and scanning laser. This substitution eliminates the need for complex image processing while achieving high-speed eye position tracking without significant lag, directly resolving the contradiction between measurement capability and tracking speed.
2Measurement precision
If conventional eye-tracking systems use cameras and image processing, then measurement capability is achieved, but device size and portability deteriorate due to bulky hardware
Solution Approach 1:
The patent replaces bulky camera systems with a compact photodetector and scanning laser assembly that can be mounted on eyeglass frames. This electro-optical approach eliminates the need for large image sensors and processing hardware, achieving eye position measurement in a miniaturized form factor suitable for wearable applications.
3Measurement precision
If conventional eye-tracking systems use cameras and image processing, then measurement capability is achieved, but power consumption deteriorates due to power hungry operation
Solution Approach 1:
The patent replaces power-intensive camera and image processing systems with a low-power photodetector and scanning laser system. The electro-optical detection method requires minimal computational resources compared to image processing, dramatically reducing power consumption while maintaining eye position measurement capability for wearable applications.
4Measurement precision
If eye coils are mounted directly on the eye, then measurement precision is improved, but user comfort and safety deteriorate due to invasive placement and magnetic field requirements
Solution Approach 1:
The patent uses the cornea as an intermediary reflective surface instead of placing sensors directly on the eyeball. The scanning laser reflects off the corneal surface, and the photodetector measures the reflected light to determine eye position. This indirect measurement method eliminates the need for invasive eye coil placement and magnetic fields, improving user safety and comfort while maintaining measurement precision.
5Ease of operation
If electro-oculograms are used to track eye position, then non-invasive measurement is achieved, but measurement precision deteriorates due to blink artifacts and signal noise
Solution Approach 1:
The patent replaces electro-oculogram detection with optical reflection detection using a photodetector and scanning laser. This optical method is insensitive to electrical noise and blink artifacts that plague electro-oculograms, achieving both non-invasive operation and high measurement precision by detecting light reflected from the corneal surface rather than measuring electrical potentials.
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 provides a low-cost, high-resolution, and low-power eye-tracking solution that is more user-friendly and efficient than conventional systems, enabling applications such as virtual and augmented reality, advertising design, and health monitoring without the need for image processing or bulky hardware.
Implementation Method 1
a laser, a two-dimensional scanning mirror, a discrete detector
Implementation Method 2
a two-dimensional scanning mirror...sweeps an optical input signal over the eye
Implementation Method 3
a discrete detector...provides an electrical signal whose magnitude represents the average intensity of the reflected signal
Data Source
AI summary
A system for tracking eye location is disclosed. Systems in accordance with the present invention include a scanner for sweeping a first optical signal across the surface of an eye, a detector for detecting a second optical signal reflected from the eye, and a detection circuit for determining a maximum intensity in the second optical signal. In operation, the scanner sweeps the first optical signal over the surface of the eye while the detection circuitry determines a plurality of intensity maxima in the second optical signal. The time between the intensity maxima during the sweep is indicative of the location of the cornea within the eye surface.