Conductive Adhesive Sheet Structure for Stable Wire Contact

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Solution Overview

Problem

Conductive adhesive sheets with embedded conductive linear bodies face issues with poor contact and electrical continuity due to embedding in the adhesive agent layer, especially when attached to substrates with irregularities, leading to compromised electrical connections.

Innovation Solution

A conductive adhesive sheet design featuring a first adhesive agent layer with a storage modulus less than 2.5 × 10^5 Pa, a thermoplastic elastomer layer with a storage modulus of 2.5 × 10^5 Pa or more, and a second adhesive agent layer, ensuring the conductive linear bodies are partially exposed and maintaining surface profile, preventing embedding and enhancing electrical connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conductive adhesive sheet is attached to a substrate with large irregularities, then the adhesive coverage is improved, but the conductive linear bodies become embedded inside the adhesive agent layer causing poor electrical contact

Engineering Contradiction:
Improveelectrical contact qualityVSAvoidadhesive coverage on irregular substrates
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the physical parameter of the adhesive agent layer by controlling its storage modulus to be less than 2.5 × 10^5 Pa at 25°C. This parameter change allows the adhesive layer to remain soft and conformable to irregular substrates while preventing the conductive linear bodies from becoming embedded, thus maintaining both adhesive coverage and electrical contact quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite adhesive sheet structure combining multiple adhesive agent layers with specific storage modulus characteristics. This composite structure enables the sheet to simultaneously achieve good adhesive coverage on irregular substrates and prevent embedding of conductive linear bodies, resolving the contradiction between adhesive performance and electrical contact quality

Inventive Principle:
Principle #40Composite materials

2Strength

If uncured soft adhesive agent is applied onto the heating wire, then the adhesive strength is improved, but electric continuity between the heating wire and electrodes cannot be established

Engineering Contradiction:
Improveadhesive strengthVSAvoidelectric continuity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies parameter change by precisely controlling the storage modulus of the adhesive agent layer to be less than 2.5 × 10^5 Pa at 25°C. This ensures the adhesive remains soft enough to provide strong bonding while maintaining surface profile and preventing conductive linear body embedding, thereby preserving electrical continuity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The adhesive agent layer acts as an intermediary between the conductive linear bodies and the substrate. By controlling its storage modulus, it mediates between the conflicting requirements of strong adhesion and electrical contact, allowing both functions to coexist without compromising either

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 design effectively suppresses embedding of conductive linear bodies, ensuring improved adhesiveness and electrical connection between the conductive linear bodies and electrodes, even on substrates with large irregularities, while maintaining adhesive strength and flexibility.

Implementation Method 1

the first adhesive agent layer has a storage modulus at 25 degrees C. of less than 2.5 × 10^5 Pa; the thermoplastic elastomer layer has a storage modulus at 25 degrees C. of 2.5 × 10^5 Pa or more

Methodology Applied
Scientific EffectStorage modulus: Viscoelasticity

Data Source

PatentEP3901966B1Conductive adhesive sheet, laminate, and heating device
Publication Date: 2023.09.13 LINTEC CORP
  • EP3901966B1 patent drawingFigure 1
  • EP3901966B1 patent drawingFigure 2
  • EP3901966B1 patent drawingFigure 3

AI summary

A conductive adhesive sheet (10) includes a first adhesive agent layer (12), a second adhesive agent layer (14), and a third layer (16) interposed between the first adhesive agent layer (12) and the second adhesive agent layer (14), in which the first adhesive agent layer (12) has a storage modulus at 25 degrees C of less than 2.5 × 105 Pa, the third layer (16) has a storage modulus at 25 degrees C of 2.5 × 105 Pa or more, and a plurality of conductive linear bodies (18) are arranged to the first adhesive agent layer (12).