Multi-fiber Connector Imaging System Using Wavelength-controlled FOV Shifter

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Solution Overview

Problem

Current multifiber connector inspection systems are slow, difficult to use, and lack the reliability and ruggedness required for field applications, as they often require manual operation and large, expensive image sensors to achieve the necessary resolution and field of view.

Innovation Solution

An imaging system with a three-wavelength illumination source, a wavelength-controlled FOV shifter using dichroic beam-splitters and mirrors, and a single image sensor or multiple image sensors to capture images of the endface of multiple-fiber connectors, with optional optical path length equalizers to maintain autofocus range across different wavelengths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a very large image sensor is used to capture all fibers in the endface of multiple-fiber connectors in a single image, then the field of view and resolution requirements are met, but the sensor size, cost, and complexity increase significantly

Engineering Contradiction:
Improvefield of viewVSAvoidsensor size
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent divides the large field of view into multiple smaller fields of view by using a wavelength-controlled FOV shifter that directs different wavelengths to different spatial regions. The image sensor captures multiple smaller images sequentially by switching wavelengths, which together encompass the entire endface area. This segmentation allows using a smaller, more affordable sensor instead of requiring a very large sensor to capture everything in one shot.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If manual adapters are used for multiple-fiber connector inspection, then compatibility with single-fiber microscopes is achieved, but the inspection speed and ease of use decrease

Engineering Contradiction:
Improveconnector type compatibilityVSAvoidinspection speed
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent replaces the manual mechanical adapter system with an automated optical system. Instead of manually positioning and adjusting adapters, the system uses a wavelength-controlled FOV shifter with dichroic mirrors and an acousto-optic modulator to automatically direct illumination to different fiber groups. This automation maintains versatility for multiple connector types while dramatically improving inspection speed and ease of use.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Extent of automation

If servomotor-controlled mirrors are used to shift FOV for automatic inspection, then automation is achieved, but the system reliability and vibration tolerance decrease

Engineering Contradiction:
Improveautomatic FOV switchingVSAvoidvibration tolerance
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The patent replaces servomotor-controlled mirrors with a static optical system using dichroic mirrors and an acousto-optic modulator. The FOV switching is achieved by modulating light wavelengths rather than physically moving components. This eliminates the mechanical moving parts that are sensitive to vibration, thereby maintaining automation while significantly improving reliability and vibration tolerance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Area of stationary object

If multiple wavelengths are used to illuminate different endface sections, then the field of view is effectively multiplied, but the optical path length differences may affect autofocus range

Engineering Contradiction:
Improveeffective field of viewVSAvoidautofocus range
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent introduces an optical path length equalizer as an intermediary component in the optical system. This equalizer compensates for the different optical path lengths created by the wavelength-controlled FOV shifter, ensuring that all wavelengths maintain consistent focus. The equalizer acts as a mediator that balances the optical paths, allowing multi-wavelength illumination to expand the effective field of view without compromising autofocus precision.

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

Enables fast, reliable, and rugged automatic inspection of multiple-fiber connectors with reduced sensor costs and maintained autofocus capabilities, allowing for efficient capture of images encompassing all individual fibers in the connector endface.

Implementation Method 1

the dichroic beamsplitters and the additional mirror are positioned in the optical path in sequence, and each of the dichroic mirrors reflects one of the wavelengths generated by the illumination source and passes the remaining wavelengths

Methodology Applied
Scientific EffectDichroic reflection: Dichroic Filter

Data Source

PatentEP3523618B1Imaging system for multi-fiber optic connector inspection
Publication Date: 2021.02.17 LIFODAS UAB
  • EP3523618B1 patent drawingFigure 1~2
  • EP3523618B1 patent drawingFigure 3
  • EP3523618B1 patent drawingFigure 4~5

AI summary

A digital fiber optic connector imaging system that can automatically capture two or more images of the endface of a multifiber connector, wherein the captured images as a group have sufficient resolution and a sufficient FOV to be used to perform a manual or automatic pass-fail analysis of the endface of every fiber terminated by the connector under inspection. In one or more embodiments, the imaging system comprises an illumination source that can operate at two or more wavelengths, one wavelength at a time, and a FOV-shifting component that includes one or more, fixed dichroic mirrors and one additional dichroic or broadband mirror. In other embodiments, the imaging system comprises a single-wavelength illumination source, an image beam splitter, and two or more image sensors located on two image planes.