Light-Scanning Projector Eye Tracking for AR Glasses
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Solution Overview
Problem
Existing augmented reality systems lack effective methods for tracking eye movement, particularly in conjunction with light scanning projector systems, which are essential for enhancing user interaction and content adaptation.
Innovation Solution
An eye tracking system utilizing a light scanning projector, an eyepiece, and photodetectors to track eye orientation and motion by correlating the position of a scanned light beam with reflected intensities, enabling gaze detection and eye position tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate eye tracking hardware is added to augmented reality systems, then eye tracking capability is achieved, but device complexity increases
Solution Approach 1:
The light scanning projector is designed to perform dual functions: displaying visual content and tracking eye movements. By modulating the display light with encoded patterns and analyzing the reflected light, the same optical path and photodetectors used for display also serve for eye tracking, eliminating the need for separate dedicated eye tracking hardware
Solution Approach 2:
The patent combines the eye tracking system with the existing display system by using the display light as the illumination source for eye tracking. The photodetectors, optical paths, and processing electronics are shared between display and eye tracking functions, merging two systems into one integrated unit
2Measurement precision
If dedicated eye tracking hardware is implemented, then eye tracking precision is improved, but manufacturing complexity increases
Solution Approach 1:
The same optical components, photodetectors, and processing electronics are used for both display and eye tracking functions. The light scanning projector generates display content while simultaneously encoding eye tracking information in the reflected light, allowing precise eye tracking without additional manufacturing complexity
Solution Approach 2:
The display system serves itself by using its own emitted light as the illumination source for eye tracking. The reflected display light contains encoded information about eye position and movement, which is detected and processed by the existing system components, eliminating the need for separate illumination sources and tracking hardware
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
Enables accurate eye tracking in conjunction with waveguide displays, reducing system complexity by using display light for input radiation, and allowing for dynamic content adaptation based on eye movement.
Implementation Method 1
a light scanning projector coupled to the pair of glasses and operable to scan a beam of light
Implementation Method 2
one or more photodetectors coupled to the pair of glasses and a processor coupled to the light scanning projector and the one or more photodetectors
Data Source
AI summary
An eye tracking system includes a pair of glasses including two frames, a projector coupled to the pair of glasses and operable to project a beam of light, and an eyepiece mounted in one of the two frames and optically coupled to the projector. The eyepiece is operable to direct at least a portion of the beam of light towards an eye of a user. The eye tracking system also includes one or more optical sensors coupled to at least one of the two frames of the pair of glasses and operable to detect a set of reflected signals off the eye of the user, and a processor coupled to the projector and the one or more optical sensors, wherein the processor is operable to determine an eye orientation based on the set of reflected signals.