Waveguide Eye Tracking System with Tunable Optical Elements
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Solution Overview
Problem
Conventional waveguide eye tracking systems face challenges in achieving a larger field of view (FOV) without increasing manufacturing cost, power consumption, or reducing image resolution, especially when attempting to incorporate face tracking alongside eye tracking.
Innovation Solution
Combining large FOV waveguide eye tracking with switchable/tunable optical elements, such as polarization tiling, spatial tiling, and wavelength tiling, along with beam steering devices, to enable high-resolution small FOV eye tracking and low-resolution large FOV face tracking, thereby reducing the need for additional camera sensors and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the field of view (FOV) is increased to enable face tracking, then the tracking coverage is improved, but the image resolution deteriorates
Solution Approach 1:
The patent divides the field of view into multiple discrete regions using beam steering devices. Each region can be independently imaged by the camera sensor, allowing the system to maintain high resolution for specific areas (eye tracking) while covering a larger overall field of view (face tracking) through sequential scanning of multiple segmented regions.
Solution Approach 2:
The patent employs dynamic beam steering devices that can rapidly change the direction of light paths to redirect different regions of the scene onto the camera sensor. This dynamic redirection allows a single camera to sequentially capture multiple regions, effectively providing both large FOV coverage and high resolution for tracked features.
2Measurement precision
If additional camera sensors are added to maintain resolution with larger FOV, then the image resolution is improved, but the manufacturing cost increases
Solution Approach 1:
The patent makes a single camera sensor perform multiple functions by using beam steering devices to direct different regions of the scene onto the same sensor. The camera thus serves both eye tracking and face tracking purposes, eliminating the need for multiple dedicated camera sensors and reducing manufacturing costs.
Solution Approach 2:
The patent introduces beam steering devices as intermediary optical elements between the scene and the camera sensor. These intermediaries dynamically redirect light from different spatial regions to the sensor, enabling a single sensor to capture multiple regions without requiring additional sensors.
3Adaptability or versatility
If additional camera sensors are added to enable face tracking, then the tracking capability is improved, but the power consumption increases
Solution Approach 1:
The patent enables a single camera sensor to perform both eye tracking and face tracking functions by using beam steering devices to sequentially direct different regions onto the sensor. This multi-functional approach eliminates the need for additional camera sensors, thereby reducing power consumption while maintaining versatile tracking capability.
Solution Approach 2:
The patent employs periodic scanning of different regions using beam steering devices. The system sequentially directs various regions of the scene onto the camera sensor in a time-multiplexed manner, allowing a single sensor to gather information from multiple areas through periodic redirection rather than continuous simultaneous imaging.
4Measurement precision
If the number of camera pixels is increased to maintain resolution with larger FOV, then the image resolution is improved, but the manufacturing cost increases
Solution Approach 1:
The patent segments the large field of view into multiple smaller regions that can be sequentially imaged by the same camera sensor. This segmentation approach allows the system to maintain high resolution for each region without requiring a sensor with a prohibitively large pixel count, thereby reducing manufacturing costs.
Solution Approach 2:
The patent uses dynamic beam steering to sequentially direct different regions onto the camera sensor. This dynamic approach allows a single sensor with a fixed pixel count to effectively capture multiple regions at high resolution by time-multiplexing the imaging process, avoiding the need for a more expensive high-resolution sensor.
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 allows for efficient eye and face tracking without increasing the number of camera pixels, thus saving cost and power while maintaining image quality, by dynamically adjusting the field of view using tunable optical elements.
Implementation Method 1
a waveguide, a first deflector element to reflect captured light to propagate in the waveguide
Implementation Method 2
a second deflector element to reflect the propagated light out of the waveguide
Data Source
AI summary
Augmented and/or virtual reality (AR/VR) near-eye display devices implementing large field of view (FOV) waveguide (WG) eye tracking combined with switchable/tunable optical elements to enable both eye and face tracking are disclosed. In particular, an eye tracking system for an augmented reality/virtual reality (AR/VR) display device may comprise a waveguide, a first deflector element to reflect captured light to propagate in the waveguide, a second deflector element to reflect the propagated light out of the waveguide, an optical element to guide out-coupled light into an eye tracking camera, and a controller to manage the optical element such that a small FOV image of an eye is captured in a first time frame and a large FOV image of a region around the eye is captured in a second time frame.