Conductive Ink Wiring on Bent Substrates

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Solution Overview

Problem

Existing methods for forming wiring on three-dimensionally shaped bases result in low mechanical strength, leading to a high probability of damage such as cracks or peeling during bending deformation.

Innovation Solution

The method involves forming one or more ink layers of electrically conductive ink on a sheet-like base before bending deformation, allowing the ink layer to remain pliable during bending and preventing damage by curing the ink layer after deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If wiring is formed on a three-dimensionally shaped base using conventional methods, then the wiring can be formed on the base, but the mechanical strength is low and the wiring has a high probability of suffering damage such as cracks or peeling during bending deformation

Engineering Contradiction:
Improvemechanical strength of wiringVSAvoidprobability of wiring damage
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The base is plastically deformed and elastically flattened before the ink layer is formed. This preliminary action allows the base to be pre-shaped while providing a flat surface for accurate wiring formation, and the elastic restoration after flattening assists in achieving the final bent shape without damaging the wiring

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of forming wiring on an already bent base (conventional approach), the invention inverts the sequence by first forming wiring on a flat base, then deforming the base. This reversal prevents wiring damage during deformation since the wiring is already cured and rigid on the flat base

Inventive Principle:
Principle #13The other way round (Inversion)

2Strength

If the base is bent-deformed before the ink layer is cured, then the ink layer remains pliable preventing breakage during bending, but the wiring formation process becomes more complex

Engineering Contradiction:
Improveintegrity of ink layer during bendingVSAvoidcomplexity of wiring formation process
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention changes the physical state parameter of the ink layer from uncured (pliable) to cured (rigid) at a specific point in the process. The ink layer is applied in a pliable state to accommodate base deformation, then cured to provide mechanical strength and electrical continuity, optimizing both flexibility during forming and strength in the final product

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The base deformation process is segmented into two distinct phases: plastic deformation to create the permanent bent shape, and elastic flattening to provide a flat surface for ink application. This segmentation allows each phase to optimize for its specific function without interfering with the other

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the base is elastically flattened before printing, then the base can be easily bent after printing with minimal contact needed on the printed surface, but the base requires additional processing steps

Engineering Contradiction:
Improveease of bending after printingVSAvoidnumber of processing steps
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The base undergoes preliminary plastic deformation and elastic flattening before the ink layer is applied. This preliminary preparation creates optimal conditions for subsequent printing and final bending, allowing the base to be easily deformed after printing with minimal contact on the printed surface while maintaining a systematic production process

Inventive Principle:
Principle #10Preliminary action

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 enhances the mechanical strength of the wiring, minimizing damage and ensuring electrical continuity while allowing for easy bending and retention of the bent shape.

Implementation Method 1

one or more ink layers of an electrically conductive ink is formed on a sheet-like base, followed by bent-deforming the base before the ink layer is cured and further followed by curing the base, to thereby form wiring

Methodology Applied
Scientific EffectCuring: Photopolymerisation

Implementation Method 2

The base 2 elastically restores as it is released from the flattened state, thereby bend-deforming at least part of the base after printing

Methodology Applied
Scientific EffectElastic restoration: Elastic Recovery

Data Source

PatentEP3232744B1Printed wiring board and manufacturing method for same
Publication Date: 2022.05.04 TOPPAN HOLDINGS INC
  • EP3232744B1 patent drawingFigure 1~2
  • EP3232744B1 patent drawingFigure 3~4
  • EP3232744B1 patent drawingFigure 5~6

AI summary

An ink layer of an electrically conductive ink is formed on a sheet-like base (2) and then the base (2) is bent-deformed before the ink layer is cured, followed by curing the ink layer, thereby forming wiring (3). The ink layer is pliable during the bending deformation of the base (2), preventing breakage of the ink layer associated with the bending deformation of the base (2), and preventing damage to the wiring (3) even when the wiring (3) is finely formed.