Offner Relay Pupil Tracking for Stable Retinal Imaging

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Solution Overview

Problem

Existing technologies face challenges in recording stable image data of the eye over time due to pupil movement, which affects the monitoring of eye health, particularly for conditions like Age-related Macular Degeneration.

Innovation Solution

An optical system with a moveably mounted offner relay that tracks the pupil's location using a tracking unit, comprising a primary and secondary reflector, and a method to determine the pupil's location from multiple images, allowing continuous imaging of the retina through the pupil over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pupil position is fixed, then the imaging system can maintain stable alignment, but the pupil moves over time causing misalignment and image degradation

Engineering Contradiction:
Improvealignment stabilityVSAvoidimaging duration
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The offner relay is made movable rather than fixed, allowing it to dynamically adjust its position to track the moving pupil. The relay can move in three dimensions (x, y, z) to maintain proper optical alignment with the pupil throughout the imaging period, thereby extending the duration over which stable retinal images can be captured.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A tracking unit continuously monitors the pupil position and provides feedback signals to control the movement of the offner relay. This closed-loop feedback system ensures that the relay maintains accurate alignment with the pupil despite physiological movements, resolving the contradiction between alignment stability and imaging duration.

Inventive Principle:
Principle #23Feedback

2Reliability

If the offner relay is made movable to track pupil movement, then imaging stability is improved, but the device complexity increases

Engineering Contradiction:
Improveimaging stabilityVSAvoidoptical system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The offner relay serves multiple functions: it directs illumination light to the eye, collects reflected light from the retina, and simultaneously acts as the tracking element that moves with the pupil. This multi-functionality reduces the need for separate tracking mechanisms, thereby limiting the increase in device complexity while maintaining imaging stability.

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

Solution Approach 2:

The tracking function is merged with the light directing function by making the offner relay itself the moving element. Instead of having a separate tracking system, the relay's movement combines both the optical path adjustment and pupil tracking, simplifying the overall system architecture while achieving stable imaging.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If the offner relay tracks pupil movement in three dimensions, then alignment accuracy is improved, but the manufacturing and control complexity increases

Engineering Contradiction:
Improvepupil tracking accuracyVSAvoidrelay assembly ease
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The three-dimensional movement capability is achieved by segmenting the adjustment into independent x, y, and z directional movements. This allows each degree of freedom to be controlled and manufactured separately, making the complex three-dimensional tracking more manageable and easier to assemble while maintaining high tracking accuracy.

Inventive Principle:
Principle #1Segmentation

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

Enables stable imaging of the retina over extended periods by accurately tracking the pupil's movement, even in three dimensions, thereby providing reliable image data for monitoring eye health.

Implementation Method 1

The offner relay may comprise a primary reflector and a secondary reflector. A first portion of the primary reflector may be arranged to reflect light from the eye towards a second portion of the primary reflector via the secondary reflector.

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3435839B1Imaging a retina of an eye
Publication Date: 2021.09.08 UNITED KINGDOM RESEARCH AND INNOVATION
  • EP3435839B1 patent drawingFigure 1
  • EP3435839B1 patent drawingFigure 2~3
  • EP3435839B1 patent drawingFigure 4~5

AI summary

Embodiments of the present invention provide an optical system (100) for imaging a retina through a pupil of an eye (10). The optical system (100) comprises an illumination source (120) for providing light to illuminate the eye (10) via an illumination optical system (140). The optical system further comprises an imaging device (130) for outputting image data corresponding to the retina of the eye (10) over a period of time. Said imaging device (130) is arranged to receive reflected light from the eye (10) via an imaging optical system (150). The optical system (100) further comprises a moveably mounted offner relay (110) arranged to direct light received from the illumination optical system (140) to the eye (10) and to direct reflected light from the eye (10) to the imaging optical system (150). Said offner relay (110) is arranged to move to track a location of the pupil.