Head-Mounted Gaze Tracker Layout for Higher Optical SNR
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Solution Overview
Problem
Existing head-mounted devices face challenges in effectively tracking user gaze due to interference from light reflections and low signal-to-noise ratio (SNR) in gaze tracking systems, which affect the accuracy and reliability of gaze detection.
Innovation Solution
The integration of light emitters and detectors within optical modules, combined with lenses that entirely overlap the light emitters' footprint and chamfered recesses or reflectors in the display bezel, enhances the SNR of the gaze tracker by allowing more light to pass unimpeded and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light emitters are mounted on a printed circuit surrounded by the display, then the gaze tracker can detect user eye position, but light reflections and low signal-to-noise ratio interfere with accurate gaze detection
Solution Approach 1:
The patent extracts the light emitters from the standard printed circuit mounting and relocates them into dedicated recesses in the display bezel. This separation removes the light emitters from the interfering environment of the printed circuit and display, isolating them in a controlled optical environment that reduces reflections and improves signal-to-noise ratio for accurate gaze detection
Solution Approach 2:
The chamfered recesses act as an intermediary optical structure between the light emitters and the user's eye. The chamfered surfaces are specifically designed to guide and direct light from the emitters toward the eye while blocking or redirecting reflected light that would otherwise interfere with the gaze detection sensors, thus mediating the optical path to improve measurement precision
2Reliability
If lenses entirely overlap the light emitters' footprint, then more light passes unimpeded to increase signal-to-noise ratio, but the optical module complexity increases
Solution Approach 1:
The patent merges the optical functions of the lenses with the structural function of the display bezel by integrating the lenses directly into the bezel assembly. The lenses are positioned to entirely overlap the light emitters' footprint, creating a unified optical structure that maximizes light transmission while minimizing the number of separate components, thus improving reliability without proportionally increasing complexity
Solution Approach 2:
The display bezel is designed to serve multiple functions: it provides structural support for the display, houses the light emitters in recesses, and integrates the lenses that direct light to the user's eye. This multi-functional design allows the same structural element to perform optical functions, reducing the need for additional dedicated components and maintaining manufacturing feasibility while improving gaze tracking performance
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 configuration improves the signal-to-noise ratio of gaze tracking, enabling accurate and continuous gaze detection without distracting the user, and allows for biometric authentication through iris imaging.
Implementation Method 1
The gaze tracker in each optical module may include light emitters that emit light to create glints on a user's eye and light detectors that detect the light and determine the gaze of the user
Implementation Method 2
Each optical module in a head-mounted device may have a display that creates an image and corresponding lenses that provide the image to an associated eye box for viewing by a user
Implementation Method 3
The recesses may be chamfered allow light from the light emitters to pass unimpeded and increase the signal-to-noise ratio (SNR) of the gaze tracker
Data Source
AI summary
A head-mounted device may have left-eye and right-eye optical modules, each of which includes a lens barrel/support, a gaze tracker in the lens barrel, a display coupled to the lens barrel, and a plurality of lenses in the lens barrel that provide an image from the display to a corresponding eye box. The gaze tracker may include light emitters mounted on a printed circuit and light detectors. Each of the lenses may include a peripheral edge that defines a footprint that entirely overlaps a footprint of the printed circuit. The display may be mounted in a display bezel, and the display bezel may include recesses in which the light emitters are mounted. The recesses may be chamfered to increase the signal-to-noise ratio (SNR) of the gaze tracker.Alternatively or additionally, a lens and/or a reflector may overlap the light emitters to increase the SNR of the gaze tracker.