Optical Fiber Unit Coating for Dense Mounting and Side-Pressure Resistance

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Solution Overview

Problem

Existing optical fiber cables face challenges in achieving high-density mounting while maintaining side pressure resistance and preventing disconnection, especially when optical fibers have small diameters, and there is a risk of incorrect fiber identification during connections.

Innovation Solution

The optical fiber unit is designed with a coating resin that covers optical fibers with a diameter of 0.2 mm or less, providing a soft cushion function and notch parts for easy identification, housed in a tube or slot groove to maintain side pressure resistance and prevent disconnection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the diameter of the optical fiber is reduced to achieve high-density mounting, then the mounting density is improved, but the side pressure resistance deteriorates and the risk of disconnection increases

Engineering Contradiction:
Improvemounting densityVSAvoidside pressure resistance
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The patent applies this principle by introducing a cushioning member (resin layer) that wraps around and protects the small-diameter optical fibers. This flexible protective layer compensates for the reduced mechanical strength of thin fibers while enabling high-density mounting by providing external support against side pressure forces.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent implements beforehand cushioning by pre-installing a cushioning member (resin layer) around the optical fibers before they are mounted in the cable. This protective layer is positioned in advance to prevent direct contact between fibers and external pressure sources, thereby maintaining side pressure resistance even when fibers have small diameters for high-density configuration.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Quantity of substance

If the diameter of the optical fiber is reduced to achieve high-density mounting, then the mounting density is improved, but the identifiability of optical fibers deteriorates

Engineering Contradiction:
Improvemounting densityVSAvoidoptical fiber identifiability
Core Design Contradiction:
Quantity of substanceVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies color changes by providing the cushioning member (resin layer) with different colors corresponding to different optical fibers or fiber groups. This visual differentiation method enables easy identification of individual fibers or bundles even when they are tightly packed in high-density configurations, solving the problem of fiber distinguishability without increasing fiber diameter.

Inventive Principle:
Principle #32Color changes

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 solution allows for easy identification and high-density mounting of optical fibers without deteriorating side pressure resistance, reducing the risk of damage and disconnection, even with small diameters.

Implementation Method 1

a coating resin that covers the optical fiber ribbon... providing a soft cushion function

Methodology Applied
Scientific EffectCushioning effect: Damping

Data Source

PatentEP3705923B1Optical fiber unit and optical fiber cable
Publication Date: 2025.09.17 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP3705923B1 patent drawingFigure 1
  • EP3705923B1 patent drawingFigure 2
  • EP3705923B1 patent drawingFigure 3~4

AI summary

The present disclosure includes: an optical fiber ribbon including a plurality of optical fibers having an outer diameter of 0.2 mm or less and a ribbon resin that integrates the plurality of optical fibers in a parallel state; and a coating resin that covers the optical fiber ribbon. The optical fiber ribbon is in an assembled form in which the plurality of optical fibers are assembled so that a length in an arrangement direction is shorter than that of a case where the optical fibers are arranged in a row, and the optical fiber ribbon is covered with the coating resin in the assembled form.