Gaze Tracking Using Combined Light Beam Superposition

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Solution Overview

Problem

Current gaze tracking methods for near-eye displays rely on capturing video images and using infrared LEDs or lasers, which may not provide accurate and robust gaze detection, especially in varying lighting conditions and user environments.

Innovation Solution

An apparatus comprising a projection arrangement with a display element and an infrared light-source, where the display element produces a light beam that superposes with an infrared light beam to form a combined beam projected towards the user's eye, and a camera captures the reflection to determine the user's gaze, enhancing accuracy through combined light beam guidance and reflection analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If infrared LEDs or lasers are used for illuminating the eye and detecting reflections, then gaze tracking can be implemented, but the accuracy and robustness of gaze detection deteriorates in varying lighting conditions and user environments

Engineering Contradiction:
Improvegaze detection accuracyVSAvoidperformance in varying lighting conditions
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent combines visible light from the display element with infrared light from the infrared light source to create a combined light beam. This merging of light sources allows the system to benefit from both the spatial precision of the display element's visible light and the environmental robustness of infrared illumination, thereby improving gaze detection accuracy across varying lighting conditions without requiring separate illumination systems

Inventive Principle:
Principle #5Merging (Combining)

2Extent of automation

If video images are captured from the user's eye to determine gaze, then gaze tracking is achieved, but the system complexity increases due to separate illumination and detection components

Engineering Contradiction:
Improvegaze tracking capabilityVSAvoidsystem structure
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The display element serves dual functions: it acts as both the visible light source for the near-eye display and as an illumination source for infrared gaze tracking when combined with the infrared light source. This multi-functionality reduces the need for separate illumination components, thereby simplifying the overall system structure while maintaining automated gaze tracking capability

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the illumination path for gaze tracking with the existing display optical path. By combining the visible light beam from the display element with the infrared light beam through optical elements, the system creates a unified illumination system that reduces component count and simplifies the overall device architecture compared to traditional separate illumination and display systems

Inventive Principle:
Principle #5Merging (Combining)

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 solution improves gaze tracking accuracy by using a combined light beam for enhanced reflection detection, allowing for more precise determination of the user's gaze and improving user experience in augmented reality applications.

Implementation Method 1

the optical element is configured to guide the light beam and the infrared light beam such that they superpose and form a combined light beam

Methodology Applied
Scientific EffectOptical superposition: Interference

Implementation Method 2

a camera configured to capture a reflection of the infrared light beam from the eye of the user

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3318914A1Gaze tracking
Publication Date: 2018.05.09 NOKIA TECHNOLOGIES OY
  • EP3318914A1 patent drawingFigure 1
  • EP3318914A1 patent drawingFigure 2a~2c
  • EP3318914A1 patent drawingFigure 3

AI summary

An apparatus comprises a projection arrangement comprising a display element and an infrared light-source, wherein the display element is configured to produce a light beam and the infrared light-source is configured to produce an infrared light beam and the display element further comprises an optical element configured to guide the light beam and the infrared light beam such that they superpose and form a combined light beam that is projected towards an eye of a user and a camera configured to capture a reflection of the infrared light beam from the eye of the user.