Touch Sensor Net-Shaped Electrode Connection Design

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Solution Overview

Problem

Existing touch sensors face disconnections between the net-shaped electrode and the outer edge wire due to inadequate filling of the conductive composition in the intaglio, leading to unreliable conductivity.

Innovation Solution

A touch sensor design with a net-shaped electrode and an outer edge wire where the outer edge wire has a large-width portion that gradually widens at the connection point, and a production method involving a recess pattern with a large-width recess, ensuring proper filling and integration of the conductive paste to prevent disconnections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the outer edge wire and conductive mesh are printed simultaneously using the same intaglio, then the manufacturing process is simplified and productivity is improved, but disconnections occur between the conductive mesh and outer edge wire due to inadequate conductive composition filling

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidconductivity reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by creating a large-width portion at the connection region between the conductive mesh and outer edge wire. This localized structural modification ensures adequate filling of conductive composition in the critical connection area while maintaining the overall simplicity of the simultaneous printing process. The large-width portion acts as a filling guide, concentrating the conductive paste in the connection region to prevent disconnections.

Inventive Principle:
Principle #3Local quality

2Productivity

If the conductive composition is not appropriately filled in the intaglio, then the printing process is simpler and faster, but disconnections occur between the conductive mesh and outer edge wire

Engineering Contradiction:
Improveprinting speedVSAvoidconductive composition filling precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements preliminary action by pre-forming a large-width portion in the intaglio structure at the connection region before the printing process. This pre-designed geometric feature guides the conductive composition filling during printing, ensuring precise and adequate filling in the critical connection area without requiring complex filling control mechanisms, thus maintaining high printing speed while improving filling precision.

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

The solution effectively suppresses disconnections between the net-shaped electrode and the outer edge wire, ensuring reliable conductivity and improved durability against bending stress.

Implementation Method 1

a net-shaped electrode which is provided on a substrate and includes conductive wires arranged in a net form; and an outer edge wire which is provided in at least a part of an outer edge of the net-shaped electrode and is integrally formed with the net-shaped electrode

Methodology Applied
Scientific EffectGravure offset printing:

Data Source

PatentEP2980680B1Touch sensor and production method for same
Publication Date: 2018.02.21 FUJIKURA LTD
  • EP2980680B1 patent drawingFigure 1
  • EP2980680B1 patent drawingFigure 2
  • EP2980680B1 patent drawingFigure 3

AI summary

A touch sensor (2) includes: a substrate (21); a net-shaped electrode (22) which is provided on the substrate (21) and includes conductive wires (221) arranged in a net form; and an outer edge wire (23) which is provided in at least a part of an outer edge of the net-shaped electrode (22) and is integrally formed with the net-shaped electrode. The conductive wire (221) includes a large-width portion which is provided in at least one of lateral parts of a connection portion and gradually widens according to approaching the outer edge wire (23), and the connection portion is a portion of the conductive wire (221) which is connected to the outer edge wire (23). Expressions (1) and (2) are satisfied: A≤100μm B/A≥1/2 In Expressions (1) and (2), "A" is a width of the outer edge wire (23), and "B" is a largest width of the conductive wires (221) in a portion where the large-width portion (222) is provided.