GI Optical Waveguide Manufacturing via Needle Injection

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Solution Overview

Problem

Current methods fail to produce GI optical waveguides with high heat resistance above 300°C and low propagation loss in the long wavelength range, particularly for opto-electronic circuit boards, due to materials with absorption issues in the long wavelength band.

Innovation Solution

A production method using a polymerizable composition comprising a reactive silicone compound and a di(meth)acrylate compound, with specific formulations for the cladding and core materials, allowing for the formation of GI optical waveguides with high heat resistance and low light propagation loss through a needle-like portion injection process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If vinyl-based silicone compound is used for optical waveguide, then heat resistance to 300°C or higher is achieved, but propagation loss in long wavelength range increases due to absorption

Engineering Contradiction:
Improveheat resistanceVSAvoidpropagation loss
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The patent changes the chemical composition parameters of the silicone compound by introducing specific phenyl groups and controlling the ratio of methyl groups to phenyl groups (where the number of phenyl groups is 1-4 per molecule). This parameter optimization reduces absorption in the long wavelength range while preserving heat resistance above 300°C.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system by combining reactive silicone compounds with specific structures (containing phenyl groups) with polymerizable groups, forming a graded-index optical waveguide that simultaneously achieves low propagation loss and high heat resistance through material composition design.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If step-index structure is used for optical waveguide, then processability is improved, but crosstalk occurs with narrow pitch cores

Engineering Contradiction:
ImproveprocessabilityVSAvoidcrosstalk
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent implements local quality by creating a graded refractive index distribution within the core, where the refractive index is highest at the center and gradually decreases toward the cladding. This local variation in optical properties confines light more effectively to the core center, eliminating crosstalk between adjacent cores while maintaining manufacturing feasibility.

Inventive Principle:
Principle #3Local quality

3Object-generated harmful factors

If graded-index structure is used for optical waveguide, then crosstalk is eliminated, but manufacturing complexity increases due to difficulty in producing refractive index gradient

Engineering Contradiction:
ImprovecrosstalkVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent simplifies manufacturing by changing the approach to creating the graded index: instead of complex post-processing, the refractive index gradient is formed directly during material synthesis by controlling the spatial distribution of phenyl groups and polymerizable groups. The needle-like portion injection method enables straightforward fabrication of the gradient structure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a needle-like portion as an intermediary tool to inject the core material into the cladding, enabling precise formation of the graded-index structure through a simple injection process rather than complex manufacturing steps.

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

The method enables the production of GI optical waveguides with excellent optical characteristics, including high refractive index and low propagation loss, suitable for use in opto-electronic circuit boards, particularly in the long wavelength range of 1,550 nm, and supports high heat resistance during solder reflowing processes.

Implementation Method 1

a polymerizable composition including a reactive silicone compound having a certain structure in combination with a di(meth)acrylate compound or an aromatic vinyl compound having a certain structure is used as a cladding material or a core material of an optical waveguide

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

a reactive silicone compound (a) composed of a polycondensate of a diarylsilicic acid compound A of Formula [1] and an alkoxy silicon compound B of Formula [2]

Methodology Applied
Scientific EffectPolycondensation:

Implementation Method 3

a core and cladding define an interface between refractive indices, and reflection at the interface allows light to propagate

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 4

in the GI structure, the refractive index is highest at the core center and gradually decreases outward. This structure allows light to be guided and propagate only in the vicinity of the core center

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3367144B1Manufacturing method for GI optical waveguide
Publication Date: 2020.03.04 NISSAN CHEM CORP
  • EP3367144B1 patent drawingFigure 1~3
  • EP3367144B1 patent drawingFigure 4(A)~4(B)
  • EP3367144B1 patent drawingFigure 5(A)~6

AI summary

There is provided a production method for an optical waveguide comprising: a first step of inserting a needle-like portion at a tip end of an ejection unit into uncured cladding; a second step of moving the needle-like portion in the uncured cladding while ejecting an uncured material from the needle-like portion to form an uncured core surrounded and covered with the uncured cladding; a third step of removing the needle-like portion from the uncured cladding; and a fourth step of curing the uncured cladding and the uncured core, wherein the uncured cladding is at least composed of a composition including a reactive silicone compound (a) composed of a polycondensate of a diarylsilicic acid compound A of Formula [1] and an alkoxy silicon compound B of Formula [2]         Ar3-Si(OR1)aR23-a     [2] and a di(meth)acrylate compound (b) of Formula [3] and the uncured core is composed of a composition including a reactive silicone compound (x) and an aromatic vinyl compound (y) of Formula [4]