Optical Fiber Coating Curing with Semiconductor UV and Heat

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Solution Overview

Problem

It is challenging to achieve an elastic modulus in optical fiber coatings comparable to those produced using high pressure mercury lamps when using semiconductor light emitting elements for curing ultraviolet curable resins, as the curing process with these elements results in incomplete crosslinking and lower glass transition temperatures.

Innovation Solution

The method involves heating the ultraviolet curable resin to a temperature equal to or higher than its glass transition temperature during curing, while irradiating it with ultraviolet light from a semiconductor light emitting element, ensuring complete crosslinking and achieving a high elastic modulus similar to that obtained with conventional high pressure mercury lamps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a semiconductor light emitting element is used as a UV light source for curing ultraviolet curable resin, then power consumption is reduced and device life is extended, but the elastic modulus of the cured coating resin decreases

Engineering Contradiction:
Improvepower consumptionVSAvoidelastic modulus
Core Design Contradiction:
Use of energy by moving objectVSStrength

Solution Approach 1:

The patent applies parameter changes by controlling the temperature of the ultraviolet curable resin during curing. Specifically, the resin is heated to 50°C or higher (preferably 60-100°C) before and/or during UV irradiation from the semiconductor light emitting element. This temperature parameter change enables complete crosslinking of the resin, achieving high elastic modulus (500 MPa or more) while using the energy-efficient semiconductor light source.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of stationary object

If a semiconductor light emitting element is used as a UV light source for curing ultraviolet curable resin, then device life is extended, but curability of the coating resin is insufficient

Engineering Contradiction:
Improvedevice lifeVSAvoidcurability
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent changes the temperature parameter of the ultraviolet curable resin to 50°C or higher during the curing process. This temperature elevation accelerates the photopolymerization reaction, ensuring complete curability when using semiconductor light emitting elements with limited spectral output, thereby achieving reliable coating formation while extending device life.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If ultraviolet curable resin is cured using only UV light from a semiconductor light emitting element without heating, then the curing process is simple, but the crosslinking is incomplete and glass transition temperature is low

Engineering Contradiction:
Improvecuring process simplicityVSAvoidcrosslinking completeness
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent merges two curing approaches: thermal heating and UV irradiation. By combining heated treatment (to 50°C or higher) with UV light irradiation from the semiconductor light emitting element, the method achieves complete crosslinking and high glass transition temperature while maintaining relatively simple manufacturing processability.

Inventive Principle:
Principle #5Merging (Combining)

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

This approach allows for the production of optical fibers with high elastic modulus coatings, matching the performance of those produced with traditional high pressure mercury lamps, while reducing power consumption and extending the life of the light source.

Implementation Method 1

irradiating the ultraviolet curable resin with ultraviolet light (UV light) to cure the ultraviolet curable resin

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

heating the ultraviolet curable resin to a temperature equal to or higher than its glass transition temperature during curing

Methodology Applied
Scientific EffectThermal heating: Heating

Data Source

PatentEP3162775B1Method for manufacturing optical fiber, and device for manufacturing optical fiber
Publication Date: 2020.03.18 FURUKAWA ELECTRIC CO LTD
  • EP3162775B1 patent drawingFigure 1~2
  • EP3162775B1 patent drawingFigure 3~4
  • EP3162775B1 patent drawingFigure 5~6

AI summary

A method of producing an optical fiber, comprising: (a) a resin application step of applying an ultraviolet curable resin, onto an outer circumference of an optical fiber; (b) a heating step of heating the ultraviolet curable resin; and (c) a light irradiation step of irradiating the ultraviolet curable resin with ultraviolet light emitted from a semiconductor light emitting element, in a state in which the ultraviolet curable resin is heated, to cure the ultraviolet curable resin into a coating resin.