Touch Panel Lead Wire Structure for Scratch-Resistant Conductivity

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Solution Overview

Problem

Conductive members for touch panels are prone to increased resistance due to scratching of lead wires during manufacturing or handling, especially when wound in rolls or laminated, leading to failures in touch panel functionality.

Innovation Solution

A conductive member design where the lead wires and external connection terminals have a thicker end part compared to their center portion, with a thickness ratio of 1.50 or more, reducing the likelihood of center portion scratching by distributing rubbing forces differently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If lead wires are made with uniform thickness, then manufacturing is simple, but resistance increases due to scratching during handling and winding

Engineering Contradiction:

Improveresistance stabilityVSAvoidlead wire structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The lead wire structure transitions from uniform thickness to non-uniform thickness with a thicker end portion. This local quality change concentrates the rubbing force on the thicker end portion during handling and winding operations, protecting the thinner center portion from scratching and maintaining its low resistance properties.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If lead wires are rubbed during manufacturing processes, then handling is easier, but resistance increases due to scratching

Engineering Contradiction:

Improvehandling easeVSAvoidresistance stability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The invention converts the harmful rubbing force encountered during handling into a beneficial effect by designing the thicker end portion to absorb this force. The rubbing that would normally damage the lead wire is redirected to the thicker end portion, protecting the critical center portion and actually improving reliability while maintaining ease of handling.

Inventive Principle:

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

3Productivity

If lead wires are wound in rolls for manufacturing, then productivity increases, but resistance increases due to rubbing between conductive members

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidresistance stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The non-uniform thickness distribution with a thicker end portion creates a localized protection zone that absorbs rubbing forces during roll winding. This allows high-speed manufacturing processes to proceed without compromising the resistance stability of the lead wire center portion.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11782551B2Conductive member for touch panel and touch panel

Publication Date: 2023.10.10 FUJIFILM CORP

AI summary

A conductive member for a touch panel includes: a substrate; and a conductive layer that is disposed on at least one surface of the substrate, in which the conductive layer includes a plurality of detection electrodes and a plurality of lead wires led from the plurality of detection electrodes, an end part of the lead wire in a width direction is thicker than a center portion of the lead wire in the width direction, and a ratio of a thickness of the end part of the lead wire to a thickness of the center portion of the lead wire is 1.50 or more.