Pupil-Tracking Display Light Source for Low-Latency Exit Pupil Alignment

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Solution Overview

Problem

Existing augmented and virtual reality display systems face challenges in efficiently aligning the exit pupil with the ocular pupil, leading to optical artifacts and inefficient light utilization, particularly when the viewer's eye moves.

Innovation Solution

A display system that aligns the exit pupil with the ocular pupil by capturing images of the eye, inverting them to create a negative image, and using a light source with selectively-activated light output locations to track and adjust the exit pupil's position, ensuring efficient light utilization and reduced optical artifacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional display system uses a fixed light source position, then the device structure is simple, but the exit pupil cannot track the ocular pupil when the viewer's eye moves, leading to optical artifacts and inefficient light utilization

Engineering Contradiction:
Improvelight utilization efficiencyVSAvoiddevice structure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the light source position adjustable and trackable. The exit pupil is dynamically repositioned to follow the ocular pupil movement through a tracking mechanism, transforming a static system into a dynamic one that adapts to user eye movements, thereby maintaining high light utilization efficiency without requiring a completely complex restructured device

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback through a pupil tracking system that detects the position of the ocular pupil and uses this information to adjust the exit pupil position accordingly. This closed-loop feedback mechanism ensures the light source remains optimally positioned relative to the user's eye, improving light utilization while managing device complexity through intelligent control

Inventive Principle:
Principle #23Feedback

2Productivity

If the display system continuously tracks and adjusts the exit pupil position to align with the ocular pupil, then light utilization efficiency improves, but the device complexity increases due to additional tracking and adjustment mechanisms

Engineering Contradiction:
Improvelight utilization efficiencyVSAvoidtracking and adjustment mechanism complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing optical components that serve multiple functions. The same optical elements used for image projection also participate in pupil tracking and positioning, reducing the need for separate dedicated tracking components and thereby managing device complexity while maintaining high productivity in light utilization

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

3Manufacturing precision

If the display system uses selective light output locations to track eye position, then optical artifacts are reduced and image quality improves, but power consumption increases due to selective activation of multiple light sources

Engineering Contradiction:
Improveimage qualityVSAvoidpower consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by selectively activating only the light source locations that are currently needed for the user's viewing position. Instead of illuminating all possible output locations continuously, the system activates only the local regions corresponding to the tracked eye position, thereby maintaining high image quality while reducing overall power consumption through localized illumination

Inventive Principle:
Principle #3Local quality

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 system achieves high light utilization efficiency, reduces optical artifacts, and allows for a more compact and longer-operating display device by continuously aligning the exit pupil with the ocular pupil, enhancing image quality and reducing power consumption.

Implementation Method 1

A light source is provided and configured to emit light. An inverted image of a pupil of an eye of the viewer is displayed on the light source. Light forming the inverted image of the pupil is modulated to provide image content to the eye of the viewer.

Methodology Applied
Scientific EffectLight emission and modulation: Light

Data Source

PatentEP3762765B1Display system with low-latency pupil tracker
Publication Date: 2025.12.17 MAGIC LEAP INC
  • EP3762765B1 patent drawingFigure 1
  • EP3762765B1 patent drawingFigure 2A
  • EP3762765B1 patent drawingFigure 2B

AI summary

A display system aligns the location of its exit pupil with the location of a viewer's pupil by changing the location of the portion of a light source that outputs light. The light source may include an array of pixels that output light, thereby allowing an image to be displayed on the light source. The display system includes a camera that captures images of the eye and negatives of the images are displayed by the light source. In the negative image, the dark pupil of the eye is a bright spot which, when displayed by the light source, defines the exit pupil of the display system. The location of the pupil of the eye may be tracked by capturing the images of the eye, and the location of the exit pupil of the display system may be adjusted by displaying negatives of the captured images using the light source.