Eye Tracking Head Up Display Using Sequential IR Illumination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing eye tracking systems in wearable devices require a large number of sensors and detectors, leading to high electrical power consumption, accuracy issues due to vibrations and user morphology, and complex mechanical calibration, making them costly and unreliable for large batch manufacturing.
Innovation Solution
A system with a reduced number of IR emitters and receivers, where emitters are activated sequentially and located on the edge of a display screen to create wide lighting spots on the cornea, minimizing the impact of user morphology and vibrations, and using a single detector to measure gaze direction with improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of sensors and detectors are used to measure gaze direction, then measurement precision is improved, but device complexity and electrical power consumption increase
Solution Approach 1:
The patent divides the illumination function into multiple IR emitters positioned at different locations around the display screen, which can be activated sequentially rather than simultaneously. This segmentation allows a single detector to capture reflected light from different emitter positions, replacing the need for multiple detectors while maintaining measurement precision through time-multiplexed illumination.
Solution Approach 2:
The patent implements periodic activation of IR emitters in sequence, where each emitter is activated for a brief period followed by the next emitter. This periodic action allows the single detector to measure reflected light from each emitter position at different times, effectively capturing the same information that would require multiple simultaneous detectors, thereby reducing device complexity while maintaining measurement accuracy.
2Manufacturing precision
If narrow crosshairs-like lighting strips are used on the cornea, then lighting precision is improved, but reliability decreases due to sensitivity to vibrations, eyeblinks, and facial expressions
Solution Approach 1:
The patent positions multiple IR emitters at different locations around the display screen edge, creating lighting spots at different positions on the cornea. Each emitter provides localized illumination with specific geometric characteristics, and the combination of multiple localized spots creates a more robust measurement system that is less sensitive to local variations caused by vibrations, eyeblinks, or facial expressions.
Solution Approach 2:
The patent changes the illumination parameters by using multiple IR emitters with different positions and activation sequences, creating wide lighting spots on the cornea instead of narrow strips. This parameter change makes the measurement less sensitive to vibrations and facial expressions while maintaining positioning precision through the geometric relationship between multiple emitter-detector pairs.
3Adaptability or versatility
If mechanical adjusting means are added for calibration, then manufacturing adaptability is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical adjusting means with a software-based calibration system. The multiple IR emitters and single detector configuration provides sufficient geometric information for calibration through software algorithms that process the reflected light measurements from different emitter positions. This substitution eliminates mechanical complexity while maintaining user-specific calibration capability through computational methods.
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 reliable and cost-effective gaze direction measurement with reduced sensor count, improved accuracy, and simplified calibration through software adjustments, reducing manufacturing tolerances and user-specific calibration needs.
Implementation Method 1
each IR emitter having a light emission cone and emitting a beam directed toward the eye of the user so as to create a lighting spot on the cornea
Implementation Method 2
the detection is performed by the difference in reflectivity of the sclera, the iris and the pupil
Implementation Method 3
at least one IR receiver set on an edge of the screen... the detection is performed by the difference in reflectivity
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention pertains to system for measuring a gaze direction of a user comprising a headpiece (100) featuring a display screen (111) set in front of the user eye and comprising a plurality of at least 3 emitters (131, 132, 133, 134, 135, 136) attached to the edges of the screen in separated locations, each IR emitter having a light emission cone and emitting a beam directed toward the eye of the user so as to create a lighting spot on the cornea, further comprising at least one IR receiver (142, 145) set on an edge of the screen, wherein the IR emitters are activated one at a time in sequence.