Flexible RFID Tag Adhesive Bonding for Curved Surfaces

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Solution Overview

Problem

Existing RFID tag manufacturing methods face challenges with high heat resistance requirements, material costs, and stress concentration issues when using flexible radiation conductor base materials, particularly when affixing to curved surfaces, leading to potential connection destruction.

Innovation Solution

A wireless communication device design featuring a flexible radiation conductor base material with belt-shaped radiation conductors and a seal with adhesive regions, allowing for slidable terminal electrode connections that maintain stable electrical contact without mechanical bonding, enabling the use of inexpensive materials like PET and reducing manufacturing time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If connection by heating and melting of solder is used, then reliable electrical connection is achieved, but high heat resistance materials are required increasing cost

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmaterial cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the thermal field (heating and melting) with a mechanical field (ultrasonic vibration) to achieve bonding. The ultrasonic bonding device uses high-frequency mechanical vibrations to melt and bond the solder bump, eliminating the need for high-temperature heating processes and allowing the use of flexible, low-cost materials like PET for the radiation conductor base material.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If connection by ultrasonic bonding is used, then flexible materials can be employed, but bonding time increases

Engineering Contradiction:
Improvematerial flexibilityVSAvoidbonding speed
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent optimizes the ultrasonic bonding parameters including vibration frequency, amplitude, and bonding pressure to achieve fast bonding speeds. By carefully controlling these parameters, the bonding process is completed in a very short time, maintaining high productivity while enabling the use of flexible radiation conductor base materials that can be bent without damaging the connection.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If flexible radiation conductor base material is used, then adaptability to curved surfaces is improved, but stress concentration destroys connection

Engineering Contradiction:
ImproveflexibilityVSAvoidconnection stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs a seal structure that surrounds the RFIC element and the connection region between the radiation conductor and the RFIC element. This seal provides mechanical support and protection to the connection region, cushioning the stress that would otherwise concentrate on and damage the connection when the flexible radiation conductor base material is bent or deformed.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 design ensures stable electric connections, reduces material costs, and prevents connection destruction when the radiation conductor base material is bent, while simplifying the manufacturing process and maintaining desired communication characteristics.

Implementation Method 1

an adhesive material is applied to a lower surface of the seal base material

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

allowing for slidable terminal electrode connections that maintain stable electrical contact without mechanical bonding

Methodology Applied
Scientific EffectFriction contact: Friction

Data Source

PatentEP3719707B1Wireless communication device and method for manufacturing same
Publication Date: 2021.11.10 MURATA MFG CO LTD
  • EP3719707B1 patent drawingFigure 1A~1B
  • EP3719707B1 patent drawingFigure 2A~2C
  • EP3719707B1 patent drawingFigure 3A~3C

AI summary

A wireless communication device includes a radiation conductor base material (12) including a radiation conductor (14a, 14b) and having a principal surface on which the radiation conductor (14a, 14b) is provided, and a radio frequency integrated circuit, RFIC, element (16) having a principal surface on which a terminal electrode (16a, 16b) is formed. The RFIC element (16) is affixed to the principal surface of the radiation conductor base material (12) with an adhesive material so that the terminal electrode (16a, 16b) faces the radiation conductor (14a, 14b). The radiation conductor (14a, 14b) entirely overlaps with the terminal electrode (16a, 16b) in a planer view of the radiation conductor base material (12).