Photocured Optical Adhesive Formulation for Ferrule Stability

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Solution Overview

Problem

Existing optical ferrule assemblies experience significant changes in beam size and insertion loss due to photodegradation of conventional photocured optical adhesives, particularly when exposed to high-intensity light over time, leading to instability in optical properties.

Innovation Solution

A photocured optical adhesive formulation comprising (meth)acrylate monomers, photoinitiators, and aliphatic urethane (meth)acrylate crosslinkers is used, with at least 98% of non-aromatic carbon-carbon bonds being single bonds, which minimizes photodegradation and maintains optical properties by eliminating double bonds, thereby stabilizing the adhesive.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional photocured optical adhesives are used in optical ferrule assemblies, then the adhesive can be cured and provide initial bonding, but the adhesive undergoes significant photodegradation when exposed to high-intensity light over time, causing changes in beam size and insertion loss

Engineering Contradiction:

Improveoptical property stabilityVSAvoidadhesive composition stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameters of the optical adhesive by eliminating non-aromatic carbon-carbon double bonds from the polymer structure. This parameter change in the molecular structure prevents photodegradation while maintaining the adhesive's bonding functionality and optical properties under high-intensity light exposure.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite material approach by combining aromatic rings with single-bond carbon chains to create a photostable polymer structure. This composite molecular structure provides both the necessary adhesive properties and resistance to photodegradation from high-intensity light exposure over time.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the optical ferrule assembly is aged at elevated temperatures and exposed to high-intensity light, then the photodegradation of the adhesive increases, but the patent maintains minimal changes in beam size and insertion loss

Engineering Contradiction:

Improveperformance consistencyVSAvoidphotodegradation effect

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potentially harmful effect of light exposure into a beneficial outcome by designing an adhesive structure that is specifically resistant to photodegradation. The aromatic ring structure with single bonds transforms the high-intensity light environment from a degrading factor into a stable operating condition, maintaining optical properties even after extended aging.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If the adhesive contains non-aromatic carbon-carbon double bonds, then the adhesive can be photocured, but these double bonds are susceptible to photodegradation under high-intensity light exposure

Engineering Contradiction:

Improvephotocuring capabilityVSAvoidlong-term optical stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the bonding parameter in the polymer structure from double bonds to single bonds in the non-aromatic portions of the molecule. This parameter change maintains the photocuring capability through aromatic ring structures while eliminating the photodegradation susceptibility associated with carbon-carbon double bonds.

Inventive Principle:

Principle #35Parameter 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 ensures that the optical ferrule assembly maintains minimal changes in beam size and insertion loss, with changes of no more than 10% and 0.3 dB respectively, even after extended aging periods, ensuring consistent performance.

Implementation Method 1

any change in the first beam size of the exiting light at the first location due to a photodegradation of the photocured optical adhesive

Methodology Applied

Scientific EffectPhotodegradation: Photo-oxidation

Implementation Method 2

A photocured optical adhesive formulation comprising (meth)acrylate monomers, photoinitiators, and aliphatic urethane (meth)acrylate crosslinkers

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS20230367083A1Optical Ferrule Assembly and Optical Adhesive Formulation

Publication Date: 2023.11.16 3M INNOVATIVE PROPERTIES CO

AI summary

An optical ferrule assembly includes an optical ferrule including an attachment area, a light input surface and a light output surface; an optical fiber having a fiber end where the light input surface and the fiber end defines a gap therebetween substantially filled with an adhesive, such that light propagating along the optical fiber and having a peak intensity I1≥3 GW/m2, exits the fiber end and enters the optical ferrule through the light input surface after traversing the gap through the adhesive, and exits the optical ferrule through the light output surface. The exiting light has a first beam size, such that after at least 100 hours of aging of the optical ferrule assembly, any change in the first beam size due to a photodegradation of the adhesive is no more than about 10%. The adhesive can be prepared by photocuring an optical adhesive formulation.