Diffractive Optical Element for Multi-View Eye Tracking
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Solution Overview
Problem
Existing near-eye display (NED) systems face challenges in accurately tracking eye movement due to the interference of secondary eye-tracking signals caused by surface reflection, which degrades signal-to-noise ratio and accuracy, especially when the user's eye moves.
Innovation Solution
The implementation of a polarization selective mechanism that separates and utilizes both diffracted primary and surface reflection secondary eye-tracking signals, providing multiple perspective views to enhance tracking accuracy through time- and spatial-multiplexing techniques using a diffractive optical element with a grating structure and polarization converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If surface reflection is utilized for eye-tracking, then additional tracking information is obtained, but signal-to-noise ratio deteriorates due to interference with primary tracking signals
Solution Approach 1:
The patent segments the eye-tracking signal into multiple independent channels based on polarization states. The primary eye-tracking signal and secondary surface reflection signal are separated into different polarization components, allowing each to be processed independently without mutual interference. This segmentation enables simultaneous utilization of both signals while maintaining high signal-to-noise ratio in each channel.
Solution Approach 2:
The patent introduces polarization selective mechanisms as intermediary elements that mediate between the mixed primary and secondary eye-tracking signals and the processing system. These intermediaries selectively transmit or block specific polarization states, enabling clean separation of the coupled signals before further processing.
2Measurement precision
If polarization selective mechanism is implemented, then multi-view eye-tracking accuracy is improved, but device complexity increases
Solution Approach 1:
The patent designs polarization selective mechanisms that serve multiple functions simultaneously: they separate primary and secondary eye-tracking signals, enable multi-view imaging, and provide polarization-based signal routing. This multi-functionality reduces the need for additional dedicated components, thereby limiting the increase in device complexity despite the enhanced capabilities.
3Measurement precision
If multiple perspective views are generated through time- and spatial-multiplexing, then tracking accuracy is enhanced, but device complexity increases due to additional optical components
Solution Approach 1:
The patent merges the functions of multiple optical components into integrated polarization selective mechanisms. Instead of using separate elements for beam splitting, filtering, and routing, the system combines these functions into unified polarization-based components that achieve the same multi-view imaging capability with fewer discrete parts.
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 significantly improves the accuracy of eye-tracking in NED systems for AR, VR, and MR applications by extracting additional information from secondary signals, leading to enhanced user experience and display quality.
Implementation Method 1
The grating structure is configured to diffract a first light having an incidence angle within a predetermined range
Implementation Method 2
the at least one substrate is configured to reflect a second light
Implementation Method 3
a polarization selective mechanism configured to generate images based on the first light and the second light, respectively
Data Source
AI summary
A system includes a diffractive optical element including at least one substrate and a grating structure. The grating structure is configured to diffract a first light having an incidence angle within a predetermined range, and the at least one substrate is configured to reflect a second light. The system also includes a polarization selective mechanism configured to generate images based on the first light and the second light, respectively.