Polarized Eyebox Illumination for Accommodation State Detection
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Solution Overview
Problem
Current eye-tracking systems in VR, AR, and MR devices face challenges in accurately determining the accommodation state of the eye, which is crucial for adjusting virtual images and calculating 3D gaze coordinates, due to limitations in illuminating and imaging the eyebox region effectively.
Innovation Solution
The use of polarized light, specifically near-infrared light, to illuminate the eyebox region, combined with polarization-sensitive sensors and scanners, allows for the determination of the accommodation state by analyzing the shape of the iris and lens, enabling precise calculation of 3D gaze coordinates and adjustment of virtual images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional illumination methods are used to image the eyebox region, then the imaging system is simple, but the accommodation state cannot be accurately determined
Solution Approach 1:
The patent changes the illumination parameter from conventional non-polarized light to polarized light, which enables the polarization-sensitive sensor to detect changes in the eye's accommodation state. This parameter change in the illumination source allows accurate measurement of the lens shape and iris curvature, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The patent introduces polarized light as an intermediary between the illumination source and the eyebox region. This intermediary enables the polarization-sensitive sensor to detect accommodation state changes by analyzing polarization angle variations, achieving accurate measurement without requiring complex multi-component illumination systems.
2Measurement precision
If polarized light is used to illuminate the eyebox region, then the accommodation state can be accurately determined, but the device complexity increases
Solution Approach 1:
The patent employs a polarization-sensitive sensor that serves multiple functions: it detects polarization angle changes caused by accommodation state variations, measures iris shape, and determines lens curvature. This multi-functionality allows accurate measurement of accommodation state while avoiding the need for separate measurement systems, thus managing device complexity.
3Measurement precision
If conventional imaging is used, then the device is simpler, but 3D gaze coordinates cannot be precisely calculated
Solution Approach 1:
The patent implements a feedback mechanism where the polarization-sensitive sensor continuously monitors polarization angle changes in the reflected light from the eyebox region. This feedback information about accommodation state changes is used to dynamically adjust and precisely calculate 3D gaze coordinates, improving measurement precision while managing system complexity through algorithmic processing.
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 enables accurate determination of the eye's accommodation state, allowing for improved adjustment of virtual images and precise calculation of 3D gaze coordinates, enhancing the functionality of VR, AR, and MR devices.
Implementation Method 1
A first polarized image of an eye in an eyebox region is captured while a polarized light illuminates the eyebox region. A second polarized image of the eye is captured while a polarization angle of the polarized light has changed.
Data Source
AI summary
An eyebox region is illuminated with polarized light. A polarized image of an eye in the eyebox regions is captured while the polarized light illuminates the eyebox region. The polarized image is compared to another polarized image to determine an accommodation state of the eye.