IR Illumination Module Layout for Waveguide MEMS Eye Tracking
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Solution Overview
Problem
Conventional mixed-reality systems, such as VR and AR systems, face user discomfort due to bulky eye tracking cameras positioned near the eyes, and there is a need to reduce the size of laser-based systems to accommodate more hardware at reduced costs while improving eye tracking and iris recognition.
Innovation Solution
An eye tracking illumination system using IR light passed through an integrated scanning waveguide display with RGB light, where the reflected IR light is sensed by photodetectors to perform eye tracking, eliminating the need for separate eye detection cameras and reducing the z-dimensional profile of the IR illumination module by redirecting light out of plane relative to its emission orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate eye tracking cameras are positioned near the user's eyes to perform eye tracking and iris recognition, then eye tracking functionality is achieved, but user discomfort increases due to bulky cameras obstructing the user's view
Solution Approach 1:
The patent combines the eye tracking illumination function with the existing waveguide display structure. The IR illumination device is integrated into the waveguide module, allowing the same optical path to serve both display and eye tracking purposes, thereby eliminating separate bulky cameras and reducing user discomfort
Solution Approach 2:
The waveguide module is designed to perform multiple functions: it serves as both the display waveguide for delivering visual content to the user and as the illumination path for eye tracking. By making the waveguide multi-functional, the system eliminates the need for dedicated eye tracking cameras while maintaining reliable eye tracking capability
2Reliability
If traditional laser-based eye tracking systems are used, then eye tracking is achieved, but the system size increases reducing hardware packaging efficiency
Solution Approach 1:
The IR illumination device is nested within the waveguide module structure, utilizing the existing optical path and mechanical housing. This nesting approach allows the eye tracking illumination components to be housed within the same volume as the display waveguide, significantly reducing the overall system size and improving hardware packaging efficiency
Solution Approach 2:
The patent reorients the IR illumination device to emit light perpendicular to the waveguide surface, and uses a turning optic to redirect the light path. This dimensional change in light propagation allows compact integration of the illumination path within the waveguide module volume, reducing the z-dimensional profile while maintaining eye tracking functionality
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 solution enables seamless eye tracking and iris detection without obstructive cameras, reducing user discomfort and allowing for a more compact and efficient mixed-reality system design by integrating eye tracking functions into existing components.
Implementation Method 1
a turning optic that redirects light in a direction out of plane relative to an emission orientation of the IR illumination device
Implementation Method 2
a collimating optic that collimates the redirected light
Implementation Method 3
One or more (e.g., or a plurality such as an array of) photodetector(s) are configured to capture reflected light that is reflected off of the user's eye
Data Source
Figure 1
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Figure 3A~3B
AI summary
An improved eye tracking illumination system is disclosed. The system includes (i) an RGB laser device that is associated with a first collimating optic and (ii) an IR illumination device that is associated with a second collimating optic. The system also includes a DMA that has a MEMS mirror system. The DMA optically combines IR light and RGB light to generate combined light. The combined light is then directed towards a user's eye via a transport medium (e.g., a waveguide). One or more photodetector(s) are positioned to capture reflected light that is reflected off of the user's eye. The photodetectors include an IR detector configured to detect reflected IR light off of the user's eye in order to perform eye tracking.