Optical Fiber Dual Coating for High Temperature Stability

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Solution Overview

Problem

Existing optical fibers are inadequate for harsh environments due to limited temperature resistance, complex production processes, and high attenuation, making them unsuitable for applications like aerospace, wind power, and high-temperature industrial settings.

Innovation Solution

A method for forming optical fibers involves melting a fiber preform at high temperatures, drawing it into a filament, cooling, and coating with acrylic or organic silicone resin, followed by ultraviolet solidification to achieve a temperature-resistant optical fiber with improved mechanical and optical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If polyimide coating is used for temperature resistance, then temperature resistance is improved, but production efficiency deteriorates due to low drawing speed

Engineering Contradiction:
Improvetemperature resistanceVSAvoidproduction efficiency
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The coating process is divided into multiple stages: first applying a lower-viscosity acrylic resin coating that is UV-cured, then applying a higher-viscosity organic silicone resin coating. This segmentation allows each coating to be applied under optimized conditions, with the first coating providing rapid curing and the second providing enhanced temperature resistance, thereby resolving the contradiction between temperature resistance and production efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the viscosity parameter of the coating materials by selecting acrylic resin with viscosity of 2000-5000cps for the first coating and organic silicone resin with viscosity of 3000-8000cps for the second coating. This parameter optimization enables the coating to be applied at high drawing speeds while maintaining temperature resistance up to 200°C.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If polyimide coating is used for temperature resistance, then temperature resistance is improved, but attenuation increases due to high modulus

Engineering Contradiction:
Improvetemperature resistanceVSAvoidattenuation
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The patent uses a composite coating structure combining acrylic resin and organic silicone resin. The acrylic resin provides a flexible base coating with lower attenuation, while the organic silicone resin overlay provides enhanced temperature resistance. This composite approach achieves both low attenuation and high temperature resistance, resolving the contradiction between these two properties.

Inventive Principle:
Principle #40Composite materials

3Temperature

If thermal solidification is used for coating, then temperature resistance is improved, but production speed deteriorates due to slow solidification

Engineering Contradiction:
Improvetemperature resistanceVSAvoidproduction speed
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The patent replaces thermal solidification with UV photopolymerization for coating the acrylic resin layer. This substitution enables rapid solidification at high drawing speeds while maintaining the temperature resistance benefits. The UV-cured acrylic coating is then overlaid with UV-cured organic silicone coating, achieving both high production speed and temperature resistance.

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

4Productivity

If UV solidification is used for coating, then production efficiency is improved, but process complexity increases due to heating and wrapping steps

Engineering Contradiction:
Improveproduction efficiencyVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the heating and wrapping steps from the conventional UV solidification process. By using UV-curable coatings that solidify immediately upon UV exposure during the drawing process, the patent removes the need for subsequent heating and wrapping operations, thereby reducing process complexity while maintaining high production efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

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 resulting optical fiber can maintain stable performance for long periods at temperatures up to 250 degrees Celsius, with low attenuation and high mechanical strength, enabling reliable use in harsh environments.

Implementation Method 1

melting a fiber preform at 2000 degrees Celsius and above

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

solidified by ultraviolet to obtain a primary coated filament

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP3872540B1Method for forming optical fiber
Publication Date: 2025.03.05 ZHONGTIAN TECH FIBER OPTICS
  • EP3872540B1 patent drawingFigure 1
  • EP3872540B1 patent drawingFigure 2

AI summary

The present disclosure provides an optical fiber and a method for forming the optical fiber. The method includes melting a fiber preform at above 2000 degrees Celsius and drawing the fiber preform into a filament. The filament is cooled to 45 to 55 degrees Celsius. An acrylic resin or organic silicone resin is coated on the cooled filament, which is solidified by ultraviolet to obtain a primary coated filament. An organic silicone resin is coated on the primary coated filament, solidification again by ultraviolet to obtain the optical fiber. The optical fiber of the present disclosure is formed by two coating processes with the acrylic (or the organic silicon) and the organic silicon. The diameter of the finished optical fiber reaches 245µm. The optical fiber can be used at 200 degrees Celsius for a long time, and the performances are stable. The optical fiber can also be used at 250 degrees Celsius for at least 7 days.