Gaze Tracking via Infrared Waveguide Eye Glints
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Solution Overview
Problem
Existing electronic devices, such as head-mounted devices, face challenges in accurately tracking a user's point of gaze for coordinating virtual and real-world content, as current methods may interfere with the user's view or require complex setups.
Innovation Solution
A head-mounted device with waveguides and localized output couplers that use infrared light to create eye glints, captured by cameras, allowing for precise gaze tracking without obstructing the user's view, using a common infrared light source distributed along the lens edges via light guides or molded polymer waveguides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional gaze tracking methods are used, then gaze tracking functionality is achieved, but the user's view is obstructed or the setup becomes complex
Solution Approach 1:
The patent introduces waveguides as intermediary optical elements that channel infrared light from a single source to multiple emitter locations along the lens periphery. This mediator approach enables distributed illumination without requiring multiple independent light sources, thereby maintaining gaze tracking accuracy while reducing system complexity
Solution Approach 2:
The patent replaces complex mechanical multi-source light emitter arrangements with a simplified optical waveguide system. The waveguide uses total internal reflection to transport infrared light, substituting mechanical complexity with optical elegance and achieving the same functional result with fewer components
2Illumination intensity
If multiple independent infrared light sources are used for each lens, then sufficient infrared light is provided for gaze tracking, but device complexity and power consumption increase
Solution Approach 1:
The patent merges multiple independent infrared light sources into a single common light source that feeds into a waveguide. The waveguide then distributes the infrared light to multiple emitter locations, achieving sufficient illumination intensity at all required positions while consuming power from only one source rather than multiple independent sources
Solution Approach 2:
The single infrared light source and waveguide system serves multiple functions simultaneously: it provides illumination for both left and right lens emitters, enables gaze tracking for both eyes, and reduces overall power consumption. This multi-functional design eliminates the need for separate light sources for each function
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 and unobtrusive gaze tracking, allowing the device to coordinate virtual and real-world content effectively while ensuring user privacy and compliance with privacy regulations.
Implementation Method 1
Waveguides that overlap the lenses may receive the images from the displays and may direct the images to eye boxes that are aligned with the lenses
Implementation Method 2
each of the localized output couplers of each lens may direct a beam of the infrared light out of the waveguide towards an eye surface in the eye box associated with that lens to produce an eye glint
Data Source
AI summary
A head-mounted device may include a housing having openings that receive lenses. Displays may output images. Waveguides that overlap the lenses may receive the images from the displays and may direct the images to eye boxes that are aligned with the lenses. Infrared light sources such as infrared light-emitting diodes or lasers may be used to supply infrared light to the waveguides. Each waveguide may have multiple localized output couplers that overlap the lenses. The localized output couplers of each lens each direct a beam of the infrared light out of the waveguide towards an eye surface in the eye box associated with that lens to produce an eye glint. A gaze tracker infrared camera may captured images of the eye glints to determine a user's point of gaze.