Low-Density MicroLED Light Source for See-Through Eye Tracking
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Solution Overview
Problem
Existing eye-tracking systems face challenges with oblique illumination, requiring higher optical power and more sensitive sensors due to light sources being positioned at angles away from the user's line of sight, which reduces accuracy and increases interference with visual observation.
Innovation Solution
A low-density set of inorganic microLEDs on a transparent or reflective substrate, allowing light to propagate out-of-plane and enabling direct illumination of the observer's eyes while maintaining visibility through the substrate, reducing the need for high-output light sources and improving gaze direction estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light sources are positioned at oblique angles for eye-tracking, then illumination can be provided, but optical power requirements increase and visual observation is interfered with
Solution Approach 1:
The patent transitions from planar/oblique light source positioning to three-dimensional volumetric distribution of light-emitting elements within a transparent medium. This dimensional change allows light to be emitted from multiple depths and angles simultaneously, providing effective illumination while maintaining line-of-sight transparency for visual observation.
Solution Approach 2:
The patent implements spatially varying properties within the light source medium, with light-emitting elements distributed non-uniformly throughout the volume. Different regions have different densities of emitting elements, allowing localized optimization of illumination intensity while preserving visual clarity in critical line-of-sight paths.
2Power
If higher optical power is used to compensate for oblique illumination, then illumination effectiveness improves, but system complexity and sensor sensitivity requirements increase
Solution Approach 1:
The patent divides the light source into multiple discrete light-emitting elements distributed throughout a volumetric medium. Each element emits light in specific directions, and their collective arrangement provides omnidirectional or multi-directional illumination without requiring any single element to operate at high power, thereby reducing overall system complexity.
Solution Approach 2:
The patent introduces a transparent medium as an intermediary between the light-emitting elements and the observer's eye. This medium facilitates light propagation from multiple angles and depths, effectively distributing illumination without requiring high optical power from individual sources, thereby simplifying the overall system.
3Area of stationary object
If light-emitting elements occupy larger area fractions for better illumination, then illumination coverage improves, but visual observation through the substrate is blocked
Solution Approach 1:
The patent moves from two-dimensional planar light source arrays to three-dimensional volumetric distributions. This allows light-emitting elements to occupy space throughout a transparent medium, providing comprehensive illumination coverage while maintaining line-of-sight transparency because the elements are distributed in depth rather than forming opaque planar layers.
Solution Approach 2:
The patent creates a porous or sparse volumetric structure where light-emitting elements are distributed throughout a transparent medium with sufficient spacing. This porous arrangement allows light to pass through the medium along sight lines while still providing adequate illumination coverage from multiple distributed sources.
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 allows for more accurate eye-tracking with reduced interference, enabling effective illumination and observation through the same light source, enhancing user experience and system performance.
Implementation Method 1
Each light-emitting element comprises one or more inorganic microLEDs that are arranged to generate and emit visible output light
Implementation Method 2
The substrate is transparent or reflective for visible light... enable visual observation of a scene through or reflected by the substrate
Implementation Method 3
in some instances the substrate is reflective so that the scene can be observed reflected by the substrate
Data Source
AI summary
An inventive light source includes a substrate and a set of multiple light-emitting elements. The substrate is transparent or reflective for visible light. The light-emitting elements are positioned on or within the substrate. Each light-emitting element comprises one or more inorganic microLEDs that are arranged to generate and emit visible output light to propagate out-of-plane relative to a corresponding localized area of the substrate around that light-emitting element. Each light-emitting element of the set being sufficiently small in at least one transverse dimension, and the light-emitting elements occupying a sufficiently small fraction of an areal extent of the set, so as to enable visual observation of a scene through or reflected by the substrate along a sight line that passes through the set of light-emitting elements.