Coherence-Based Eye Tracking with Selective Laser Activation
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Solution Overview
Problem
Existing eye-tracking techniques face challenges in robustness, accuracy, and efficiency, particularly in obtaining sub-surface information about the eye, and often suffer from occlusion issues and high power consumption.
Innovation Solution
The use of coherence-based measurements, such as optical coherence tomography (OCT), integrated with an integrated circuit that includes selectively activated lasers and photodiodes, allows for sub-surface eye tracking with reduced occlusion and power consumption, utilizing VCSELs and photodiodes for efficient gaze tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coherence-based measurement with integrated circuit is used, then measurement precision and robustness are improved, but device complexity increases
Solution Approach 1:
The patent merges multiple functional components (laser light sources, photodiodes, coherence measurement circuitry) into a single integrated circuit chip. This integration enables sub-surface eye tracking with high measurement precision while managing device complexity through consolidation of functions that would otherwise require separate components.
Solution Approach 2:
The integrated circuit is designed to perform multiple functions: emitting laser light, detecting reflected light through photodiodes, processing coherence signals, and determining eye position. This multi-functionality reduces the need for separate dedicated components for each function, thereby managing overall device complexity while maintaining high measurement precision.
2Adaptability or versatility
If all light sources are activated for comprehensive eye tracking, then measurement coverage is improved, but power consumption increases
Solution Approach 1:
The patent divides the light source array into multiple individually controllable light sources. The system can selectively activate only the subset of light sources needed for the current eye tracking task, rather than activating all sources continuously. This segmentation enables power consumption reduction while maintaining comprehensive coverage capability when needed.
Solution Approach 2:
The system employs periodic or intermittent activation of light sources based on eye movement detection and tracking requirements. Rather than continuous operation, light sources are activated in periodic cycles corresponding to eye movement phases, reducing overall power consumption while maintaining adequate measurement coverage during active tracking periods.
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 provides accurate sub-surface eye tracking with reduced occlusion and power consumption, enabling efficient gaze tracking and improved user interaction with electronic devices.
Implementation Method 1
The light sources may include vertical cavity surface-emitting lasers (VCSELs)
Implementation Method 2
analyze light reflected off front surfaces of the eye to estimate eye characteristics
Implementation Method 3
coherence-based measurement (e.g., optical coherence tomography (OCT))... based on reflections/scattering of light
Implementation Method 4
integrating the light sources and photodiode array into an integrated circuit/chip... reflected light of the projected light are sensed via a subset of the one or more photodiodes
Data Source
AI summary
Various implementations disclosed herein include electronic devices, systems, and methods that determine a current position of a portion of an eye based on coherence-based measurements. An example electronic device may include a tracking component that includes an integrated circuit that includes a plurality of lasers and one or more photodiodes. An example method may include determining an expected position of a portion of an eye relative to the tracking component. The method may further include selectively activating a subset of the plurality of lasers to project light towards the portion of the eye, wherein reflected light of the projected light are sensed via a subset of the one or more photodiodes based on the expected position of the portion of the eye. The method may further include determining a current position of the portion of the eye based on coherence-based measurements using the projected light and the reflected light.