Flexible RFID Layer Structure with Integrated Circuit

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Solution Overview

Problem

Conventional passport covers with integrated RFID chips and antennas face challenges in balancing flexibility with adequate protection and integration, often resulting in structures that are either too stiff or insufficiently protective, and struggle to maintain a flush integration of the chip and antenna within the cover layers.

Innovation Solution

A flexible multilayer structure utilizing nonwoven materials with cavities filled with a flexible thermoplastic adhesive, where the nonwoven layers are designed to adapt to the chip's dimensions and provide optimal protection and flexibility, ensuring the RFID chip and antenna are seamlessly integrated without bulkiness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the passport cover is made with simple paper layers, then flexibility is maintained, but protective effect for the chip and antenna becomes insufficient

Engineering Contradiction:
ImproveflexibilityVSAvoidprotective effect
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent uses a composite multilayer structure combining paper layers with a foam layer having open cells. The foam layer serves as both protective cushioning for the chip and antenna while maintaining flexibility. The open cells can be filled with adhesive to secure the electronic components, creating a composite material system that simultaneously provides protection and flexibility.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the passport cover is made stiff to protect the chip, then protective effect is improved, but flexibility for common use deteriorates

Engineering Contradiction:
Improveprotective effectVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent employs a foam layer with open cells that acts as a flexible protective shell. This foam structure provides cushioning and protection for the chip and antenna while inherently maintaining flexibility due to its cellular structure. The foam can be filled with adhesive through the open cells to secure components without compromising the overall flexibility of the cover.

Inventive Principle:
Principle #30Flexible shells and thin films

3Strength

If the chip is placed in a recess higher than the overall height of the chip, then pressure load protection is improved, but bending stress protection deteriorates and the cavity becomes a weak point

Engineering Contradiction:
Improvepressure load protectionVSAvoidbending stress protection
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the parameter of the recess depth to be substantially equal to the overall height of the chip, eliminating the cavity that acts as a weak point. The foam layer's cellular structure provides the necessary cushioning without requiring an oversized recess, thus protecting against both pressure and bending stresses simultaneously.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If resin embedding is used to protect the chip, then protective effect is improved, but flexibility and adaptability deteriorate

Engineering Contradiction:
Improveprotective effectVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent uses a foam layer with open cells instead of solid resin embedding. The porous structure of the foam provides protection while allowing the layer to remain flexible and adaptable. The open cells can be filled with adhesive to secure the chip, but the overall foam structure maintains its flexibility and ability to adapt to different configurations.

Inventive Principle:
Principle #31Porous materials

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 provides a robust and flexible passport cover that effectively protects the RFID components while maintaining the passport's flexibility, ensuring the chip and antenna are securely embedded without visible or palpable protrusions, enhancing both security and usability.

Implementation Method 1

at least one of the layers is formed from a nonwoven material, the cavities of which are essentially filled with a flexible thermoplastic adhesive

Methodology Applied
Scientific EffectThermoplastic adhesive bonding: Adhesive

Data Source

PatentEP2084654B1Flexible layer structure with an integrated circuit
Publication Date: 2012.10.17 LOBRA AG
  • EP2084654B1 patent drawingFigure 1a~1c
  • EP2084654B1 patent drawingFigure 2a~2c
  • EP2084654B1 patent drawingFigure 3

AI summary

A flexible multilayer structure (1) is described with a RFID chip (10) and an antenna (8), wherein the RFID chip (10) and the antenna (8) are integrated in the multilayer structure (1) in such a way that they do not bear against anything. A particularly robust flexible structure which protects the chip and the antenna and yet which is long lasting and unbreakable is provided, in that at least one of the layers (3-6) is made from a nonwoven material or an open cell foam, the cavities of which are largely filled with a flexible adhesive. A method for the production of such a multilayer structure is also described, which method is characterized in that at least one of the layers (3-6) made from a nonwoven material or an open cell foam is applied in a relaxed, non-compressed state, the cavities thereof being filled with the adhesive in the liquid state to 70% to 85% of their volume, and in that, during the bonding with other layers (2-7) and/or in a final fusion process, the filled nonwoven material or open cell foam is compressed and, if necessary, heat treated in such a way that the cavities in the finished multilayer structure are at least 90% full.