Keep-out Zone for In-field Light Sources in HMD Eye Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional head-mounted displays (HMDs) with eye-tracking systems face interference from illumination light sources placed outside the field of view, which can impede the detection of specular reflections and reduce the accuracy and speed of eye-tracking measurements.
Innovation Solution
Incorporating a near-eye optical element with in-field light sources, such as micro-LEDs or VCSEL diodes, that are small enough to be unnoticeable and can be actively controlled based on eye location or predicted future location to avoid occluding specular reflections, using a keep-out zone or selective enabling/disabling of light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If illumination light sources are placed outside the field of view to illuminate the eye, then the eye can be adequately illuminated for tracking, but the light sources may impede or interfere with the eye-tracking system by occluding specular reflections
Solution Approach 1:
The patent applies local quality by creating a keep-out zone in the center of the illumination layer where light sources are excluded, while allowing light sources in peripheral regions. This spatial differentiation ensures that the eye receives adequate illumination from peripheral lights while preventing direct views of light sources from occluding specular reflections in the eye-tracking camera's field of view.
Solution Approach 2:
The patent resolves the contradiction by introducing a spatial dimension - the illumination layer positioned at a distance from the eye, with light sources arranged in a peripheral pattern rather than directly in front of the eye. This dimensional arrangement allows light to reach the eye without creating direct occluding paths to the camera.
2Ease of operation
If in-field light sources are made small to be unnoticeable to users, then user comfort is maintained, but the light sources still occupy space that could interfere with specular reflection detection
Solution Approach 1:
The patent maintains user comfort by keeping individual light sources small and unnoticeable while simultaneously creating a keep-out zone that prevents any interference with specular reflection detection. The local exclusion zone ensures that even though light sources exist, their direct views are blocked from the camera's perspective.
Solution Approach 2:
The patent extracts the problematic direct view path from the system by implementing a keep-out zone that removes the region where light sources would directly occlude specular reflections. This extraction allows the light sources to be present without compromising the camera's ability to detect reflections.
3Measurement precision
If a keep-out zone is implemented to prevent light source occlusion, then eye-tracking accuracy is improved, but the arrangement of light sources becomes more complex
Solution Approach 1:
The patent segments the illumination layer into two distinct regions: a central keep-out zone where light sources are excluded, and peripheral regions where light sources are positioned. This segmentation simplifies the overall design by creating clear spatial boundaries rather than requiring complex dynamic control systems.
Solution Approach 2:
The patent implements preliminary action by pre-defining the keep-out zone geometry and position during the design phase, rather than requiring real-time dynamic adjustment. The light sources are arranged in advance in peripheral locations that inherently avoid occluding the specular reflections, eliminating the need for complex active control.
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 enhances the accuracy and speed of eye-tracking by minimizing the impact of in-field light sources on specular reflection detection, allowing for more precise eye-tracking and power efficiency.
Implementation Method 1
In-field light sources, such as micro-LEDs or VCSEL diodes
Implementation Method 2
Incorporating a near-eye optical element with in-field light sources
Implementation Method 3
impede the detection of specular reflections
Data Source
AI summary
Aspects of an illumination layer of a near-eye optical element for a head mounted display (HMD) are provided herein. The illumination layer includes a plurality of in-field light sources and a keep-out zone. The in-field light sources are configured to emit infrared light to illuminate an eye of a user of the HMD for imaging of the eye by an eye-tracking camera. The keep-out zone includes a center that is to be aligned with a center of the eye when the eye is in a centered orientation, where the in-field light sources are arranged within the illumination layer outside of the keep-out zone.