Laser Eye Tracking Optics for Low-Power AR Headsets
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Solution Overview
Problem
Existing eye tracking technologies are high in power consumption, low in accuracy, and obstructive to the field of view, failing to provide a compact, efficient, and accurate solution for augmented reality applications.
Innovation Solution
An eye tracking device using laser light to measure corneal distances, employing an optical element with dual functions for illumination and reception paths, and multiple laser beams for improved accuracy and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If imaging sensors are used for eye tracking, then eye position can be determined, but power consumption increases and accuracy decreases
Solution Approach 1:
The patent replaces imaging sensors with a laser-based distance measurement system. Instead of capturing images and processing them to determine eye position, the system uses laser beams to directly measure distances to the cornea, substituting an optical-mechanical measurement approach for an electronic imaging approach, thereby reducing power consumption while improving accuracy
Solution Approach 2:
The patent extracts only the essential measurement function from complex imaging systems. By using laser distance measurement to directly obtain corneal position data, the system eliminates the need for image capture, processing, and analysis, keeping only the critical distance measurement capability that directly provides eye position information
2Measurement precision
If imaging sensors are placed to maximize data quality, then measurement accuracy improves, but field of view is obstructed
Solution Approach 1:
The patent removes the imaging sensor entirely and replaces it with a compact laser distance measurement system. This extraction of the measurement function to a simpler, more compact form factor eliminates the need for large sensor arrays and associated optics that obstruct the field of view, while maintaining or improving measurement accuracy through direct distance measurement
3Measurement precision
If multiple laser beams are used to improve accuracy, then measurement precision increases, but device complexity increases
Solution Approach 1:
The patent employs optical elements that perform multiple functions: beam splitting to create multiple illumination beams, polarization management to separate illumination and detection paths, and focusing to concentrate light on the cornea and collect reflections. This multi-functionality allows the system to achieve high measurement accuracy with multiple beams while avoiding proportional increases in device complexity
Solution Approach 2:
The patent combines multiple optical functions into integrated optical elements. The beam splitter, polarizers, and focusing lenses are arranged to work together as a unified optical system, where components serve multiple purposes simultaneously, reducing overall system complexity compared to separate independent subsystems
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 achieves low power consumption, high accuracy, and unobtrusive eye tracking with enhanced signal strength and flexibility in device placement, enabling precise gaze direction estimation.
Implementation Method 1
a receiver unit configured to receive reflections of the laser beam
Implementation Method 2
uses laser light to measure the distance of specific points on the cornea
Implementation Method 3
The optical element can be configured to apply the first optical function to light having a first polarisation and the second optical function to light having a second, different polarisation
Data Source
AI summary
An eye sensing device for integrating in a frame for mounting to a user's head including a laser output unit configured to provide a laser beam for illuminating an eye of the user when in use, and a receiver unit configured to receive reflections of the laser beam and to provide a tracking signal usable for determining a distance or velocity of the eye. The device further includes an optical element configured to apply a first optical function to the laser beam for illuminating the eye and to apply a second optical function to the reflections of the laser beam, and a processing unit for determining a position of the user's eye from the tracking signal.