Waveguide Outcoupling for Occlusion-Free Eye Tracking
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Solution Overview
Problem
Conventional light sources in head-mounted devices introduce significant occlusions and unwanted diffraction effects, making it challenging to illuminate an eye region without disrupting the optical system, particularly in the context of augmented and virtual reality applications where non-visible light is used for eye-tracking purposes.
Innovation Solution
A transparent waveguide structure integrated into the head-mounted device receives non-visible light from sources like LEDs or lasers and directs it to outcoupling elements across a transparent layer, minimizing occlusions and allowing for effective eye-tracking illumination without noticeable disruption to the user's field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional light sources are used to illuminate the eye region, then illumination is achieved, but significant occlusions and unwanted diffraction effects are introduced into the optical system
Solution Approach 1:
A waveguide structure serves as an intermediary between the light source and the eye region. The light source couples light into the waveguide, which then guides the light to outcoupling elements positioned near the eye. This intermediary approach allows the light source to be positioned away from the direct optical path, eliminating occlusions and diffraction effects while maintaining effective illumination for eye-tracking
Solution Approach 2:
The patent replaces direct mechanical illumination (conventional light sources positioned in the optical path) with an optical guiding system. Instead of using traditional LEDs or lamps that physically block light, the system uses waveguide structures to transport light through total internal reflection, substituting a mechanical positioning problem with an optical solution
2Reliability
If light sources are positioned to illuminate the eye region, then eye-tracking illumination is achieved, but the optical path is disrupted
Solution Approach 1:
The illumination system is segmented into distinct functional components: a light source module, a waveguide structure with multiple outcoupling elements, and an imaging module. This segmentation allows each component to be optimized independently and positioned to minimize interference with the main optical path, maintaining eye-tracking reliability without disrupting the overall optical system
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 solution enables efficient and unobtrusive illumination of the eye region using non-visible light, allowing for accurate eye-tracking while maintaining a clear optical path, reducing noticeable occlusions and diffraction effects, and allowing users to view the environment and electronic displays without interference.
Implementation Method 1
A waveguide structure receives non-visible light from one or more light sources and provides the non-visible light to a set of outcoupling elements
Data Source
AI summary
Outcoupling elements are disposed with a transparent layer. A transparent waveguide structure receives non-visible light and delivers the non-visible light to the outcoupling elements. The outcoupling elements outcouple the non-visible light as non-visible illumination light.