Broad-Line Fundus Imaging With Split Paths to Reduce Scattering

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Solution Overview

Problem

Unwanted reflections and scattering in fundus imaging systems reduce the contrast and visibility of low-level features in the eye, overwhelming the desired signal and obscuring important details.

Innovation Solution

Implementing selective illumination patterns at the pupil-splitting plane using specialized optics and illumination sources to separate illumination and detection paths, allowing for the use of dead zones and switchable optical elements to block or control light paths, thereby reducing reflections and scattering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If light is scattered by the retina and collected through optical components, then fundus imaging is achieved, but unwanted reflections and scattered light reduce image contrast and obscure low-level features

Engineering Contradiction:
Improveimage contrastVSAvoidunwanted reflections
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent divides the single optical path into separate illumination and detection paths using beam splitting optics. The illumination path delivers light to the retina while the detection path collects reflected light, preventing overlap between incident and reflected beams. This spatial segmentation eliminates unwanted reflections from optical components that would otherwise contaminate the detection path.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the harmful reflected light from the detection path using optical elements such as beam splitters and dichroic mirrors. By separating the detection path from the illumination path, the system removes unwanted reflections and scattered light that would reduce image contrast and obscure low-level retinal features.

Inventive Principle:
Principle #2Taking out (Extraction)

2Object-generated harmful factors

If separate paths for illumination and collection are used, then reflection artifacts are reduced, but device complexity increases

Engineering Contradiction:
Improvereflection artifactsVSAvoidoptical path configuration
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent introduces beam splitting optics as intermediary elements between the illumination source and the detector. These optical mediators (beam splitters, dichroic mirrors) enable the separation of illumination and detection paths while maintaining a compact integrated design. The intermediaries manage the complex optical routing without requiring completely separate optical trains, thus reducing overall system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Achieves high-resolution, artifact-free fundus images by minimizing unwanted reflections and scattering, enhancing image clarity and contrast, enabling clearer detection of low-contrast features.

Implementation Method 1

illuminating light is scattered by the retina (fundus) of the eye of a subject, and the return light is collected and detected

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

Diffuse and specular reflections from various optical components of the fundus imagers as well as the optical components of the eye such as the corneal and crystalline lens surface can contribute to unwanted light

Methodology Applied
Scientific EffectSpecular reflection: Reflection

Data Source

PatentEP3253276B1A method and apparatus for reducing scattered light in broad-line fundus imaging
Publication Date: 2025.08.13 CARL ZEISS MEDITEC AG
  • EP3253276B1 patent drawingFigure 1a~1b
  • EP3253276B1 patent drawingFigure 2a
  • EP3253276B1 patent drawingFigure 2b

AI summary

Methods and apparatuses for fundus imaging are presented that use sequential selective illumination patterns to suppress unwanted reflections, scattering and haze from various optical components of a fundus-viewing instrument. This is particularly the case with those unwanted reflections produced by the objective lens contained within said instrument.