Electroconductive Film Laser Patterning Nanowire Migration

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Solution Overview

Problem

Conductive films with indium tin oxide (ITO) face issues with flexibility, leading to cracks when used with flexible base materials, and metal nanowires in electroconductive films can cause electrical short circuits due to remaining nanowires and migrating ions during laser etching.

Innovation Solution

An electroconductive film with a light-transmitting base material, electroconductive parts containing light-transmitting resin and electroconductive fibers, and nonconductive parts with a three-dimensional arithmetic average roughness of 3 nm or more, preventing electrical short circuits by ensuring proper distribution and exposure of electroconductive fibers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ITO is used in the electroconductive film, then electrical conductivity is achieved, but flexibility is poor causing cracks on the light-transmitting electroconductive layer

Engineering Contradiction:

Improveelectrical conductivityVSAvoidflexibility

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent changes the material composition parameters by replacing ITO with metal nanowires (silver, aluminum, or copper nanowires with specific diameter ranges) combined with resin materials, achieving both electrical conductivity and flexibility through compositional modification

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite electroconductive layer combining metal nanowires with resin materials (epoxy resin, polyester resin, polyurethane resin, or acrylic resin), where the composite structure provides both the electrical conductivity of metal nanowires and the flexibility of resin materials

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If wet etching is used for patterning the electroconductive layer, then patterning can be performed, but chemical contamination may cause electrical short circuits

Engineering Contradiction:

Improvepatterning capabilityVSAvoidchemical contamination

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the chemical wet etching process with a laser-based patterning process, using light energy instead of chemical substances to remove the electroconductive layer and form patterns, thereby eliminating chemical contamination

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the patterning method parameters by selecting laser power, wavelength, and scanning speed parameters that enable precise removal of electroconductive material without causing metal nanowire migration or chemical contamination

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If laser etching is used for patterning, then chemical contamination is avoided, but metal nanowires may remain in nonconductive parts causing electrical short circuits

Engineering Contradiction:

Improvechemical contaminationVSAvoidpatterning completeness

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by performing surface treatment on the electroconductive layer before laser etching to modify surface properties, ensuring complete removal of metal nanowires in nonconductive areas and preventing residual nanowire contamination

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback control in the laser etching process by monitoring etching depth and adjusting laser parameters in real-time to ensure complete removal of electroconductive material in nonconductive parts while preserving conductive patterns

Inventive Principle:

Principle #23Feedback

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 inhibits electrical short circuits and maintains flexibility, ensuring high optical properties and durability of the electroconductive film, suitable for applications like touch panels and image display devices.

Implementation Method 1

each of the electroconductive parts contains a light-transmitting resin and an electroconductive fiber incorporated in the light-transmitting resin

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

the surface of the nonconductive part has a three-dimensional arithmetic average roughness of 3 nm or more

Methodology Applied

Scientific EffectSurface roughness:

Data Source

PatentUS11669211B2Electroconductive film, touch panel, and image display device

Publication Date: 2023.06.06 DAI NIPPON PRINTING CO LTD

AI summary

One aspect of the present invention provides an electroconductive film 10 comprising a light-transmitting base material 11, a plurality of light-transmitting electroconductive parts 12 provided on one surface 11A of the light-transmitting base material 11, and a nonconductive part 13 located between the electroconductive parts 12, wherein each of the electroconductive parts 12 contains a light-transmitting resin 15 and an electroconductive fiber 16 incorporated in the light-transmitting resin 15; the nonconductive part 13 contains a light-transmitting resin 15; and the surface 13A of the nonconductive part 13 has an arithmetic average roughness of 3 nm or more.