Lens-Embedded IR Light Sources for Single-Camera Eye Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing eye-tracking techniques in head-mounted systems lack accuracy and require multiple cameras to capture sufficient glints due to suboptimal light source placement, often on the device frame, which can lead to inaccurate gaze estimation and iris identification.
Innovation Solution
Incorporating infrared (IR) light sources, such as micro-IR LEDs, on a transparent substrate within the lens of a head-mounted device (HMD) allows for a wider placement of light sources closer to the optical axis, improving accuracy by ensuring they are not perceptible to the user and enabling better gaze direction and iris detection through a spatial arrangement that optimizes glint reflection capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If light sources are placed on the device frame, then the structure is simple, but the accuracy of gaze estimation and iris identification deteriorates
Solution Approach 1:
The patent transitions from placing light sources in the peripheral frame dimension to embedding them within the lens substrate at the optical axis center dimension. This dimensional shift positions the light sources closer to the eye's optical axis, enabling accurate glint capture for gaze estimation while maintaining structural integration within the lens assembly.
Solution Approach 2:
The patent applies local quality by embedding light sources specifically within the lens substrate at strategic locations near the optical axis, rather than uniformly distributing them around the frame. This localized placement optimizes the glint reflection geometry for accurate eye characteristic measurement while keeping the overall device structure integrated.
2Measurement precision
If multiple cameras are used to capture sufficient glints, then the measurement accuracy improves, but the device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical approach of using multiple cameras with a single camera by optimizing the light source placement and glint reflection geometry. By positioning light sources within the lens substrate near the optical axis, the system creates optimal reflection paths that enable a single camera to capture sufficient glint information for accurate eye characteristic assessment.
Solution Approach 2:
The patent changes the spatial parameters of light source placement from peripheral frame positions to central lens substrate positions near the optical axis. This parameter change in light source positioning creates optimal glint reflection geometry that maximizes the information captured by a single camera, eliminating the need for multiple cameras while maintaining measurement accuracy.
3Ease of manufacture
If light sources are placed on the frame, then the placement is straightforward, but the frame thickness must be increased to accommodate the light sources
Solution Approach 1:
The patent merges the light source function with the lens substrate structure by embedding the light sources within the lens assembly itself. This integration eliminates the need for separate frame mounting structures, allowing the lens substrate to serve both as the optical element and as the housing for the light sources, thereby reducing overall frame thickness.
Solution Approach 2:
The patent applies nesting by embedding the light sources within the lens substrate structure, placing one functional element (light source) inside another (lens assembly). This nested configuration allows the light sources to be accommodated within the existing lens thickness without requiring increased frame thickness, maintaining a compact overall structure.
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 enhances eye characteristic assessment by increasing accuracy and reducing the thickness of the frame, allowing for precise gaze estimation and iris identification using a single camera, thus improving the overall performance of eye-tracking systems.
Implementation Method 1
infrared (IR) light sources, such as micro-IR LEDs
Implementation Method 2
glint produced using a light source... a reflection of an IR LED on the eye
Data Source
AI summary
Various implementations disclosed herein include electronic devices, systems, and methods that detect reflections of light produced by a plurality of light sources reflected from an eye. An example electronic device may include a frame, an image sensor, a transparent substrate coupled to the frame, a waveguide coupled to the transparent substrate, and a processor coupled to the plurality of IR light sources. The transparent substrate may include a plurality of infrared (IR) light sources that may be configured in a spatial arrangement within the transparent substrate or on a surface of the transparent substrate. The waveguide may be configured to display a projected image. The processor may be configured to receive sensor data from the image sensor. The sensor data may correspond to a plurality of reflections of light produced by the plurality of IR light sources and reflected from an eye.