Heat Fusible RFID Tag Assembly for Textile Attachment

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Solution Overview

Problem

Existing methods for attaching RFID tags to flexible surfaces like textiles or fabrics, such as stitching or using conductive threads, result in cumbersome and inflexible solutions that suffer from electromagnetic coupling issues due to loosening threads and antenna misalignment, especially after repeated washing cycles.

Innovation Solution

A process involving a heat fusible label with a secondary antenna structure and pressure-sensitive adhesive (PSA) layer is used to attach an RFID tag to a flexible surface, ensuring secure and accurate placement through heat activation, which includes a substrate layer with conductive wire stitching or weaving and a printable layer for precise alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If stitching or bonding the RFID tag directly to the fabric, then the tag is securely attached, but the solution becomes cumbersome and inflexible

Engineering Contradiction:
Improveattachment securityVSAvoidflexibility and comfort
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention divides the RFID tag system into separate functional components: a flexible antenna element integrated into the fabric and a separate RFID tag module. This segmentation allows the antenna to remain flexible and comfortable while the tag can be securely attached using stitching or bonding without compromising overall flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a coupling mechanism that acts as an intermediary between the fabric-integrated antenna and the RFID tag. This coupling structure enables secure attachment while maintaining the flexibility of the fabric and proper electromagnetic coupling, resolving the contradiction between security and comfort.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If using conductive thread to provide secondary antenna with button stitched to fabric, then flexibility and comfort are improved, but the thread link loosens over time with washing cycles

Engineering Contradiction:
Improveflexibility and comfortVSAvoidattachment durability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention replaces the mechanical thread-linkage system with a more durable coupling mechanism that maintains electrical and mechanical connection through washing cycles. This substitution preserves flexibility while eliminating the loosening problem associated with traditional stitching.

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

3Ease of operation

If using button stitched to fabric with conductive thread, then the system is flexible, but the button rocks about or tilts, deteriorating electromagnetic coupling

Engineering Contradiction:
ImproveflexibilityVSAvoidelectromagnetic coupling alignment
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent employs a flexible coupling structure that maintains consistent electromagnetic coupling alignment while allowing the fabric to move and flex. This flexible connection prevents the button from rocking or tilting, thereby maintaining proper alignment between the primary and secondary antennas during washing and wear.

Inventive Principle:
Principle #30Flexible shells and thin films

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 method provides a flexible and durable RFID tag assembly with improved electromagnetic coupling, resistant to washing and wear, maintaining comfortable and reliable performance over time.

Implementation Method 1

applying heat and pressure to said heat fusible label to melt said heat activated layer and to fuse said label to said flexible surface

Methodology Applied
Scientific EffectHeat activation: Melting

Implementation Method 2

a pressure sensitive adhesive (PSA) layer for holding said RFID tag

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP2901374B1Improvements in RFID tag assemblies and process
Publication Date: 2019.10.23 INVENGO TECH SARL
  • EP2901374B1 patent drawingFigure 1~2
  • EP2901374B1 patent drawingFigure 3
  • EP2901374B1 patent drawingFigure 4~5

AI summary

A process is disclosed for attaching an RFID tag such as an AK module or QFP package to a flexible surface such as textile or fabric. The process comprises providing a heat fusible label including at least a first layer having a first adhesive layer, a substrate layer including a secondary antenna structure, a heat activated second adhesive layer and a pressure sensitive adhesive (PSA) layer for holding the RFID tag. The process further includes positioning the RFID tag on the PSA layer, pressing the tag against the PSA layer such that the PSA layer holds the tag against the heat fusible label at least temporarily, positioning the heat fusible label with the RFID tag on the flexible surface and applying heat and pressure to the heat fusible label to melt the heat activated layer and to fuse the label to the flexible surface.