Zigzag Inlay Wire Layout for Reliable Electronic Document Contacts

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Solution Overview

Problem

Existing methods for manufacturing electronic documents with embedded metal wires face issues such as poor contact between wire ends and modules, wire tearing during machining, and malfunctions due to loose wire portions, leading to potential short circuits and reduced connectivity.

Innovation Solution

The use of a zigzag metal wire embedded in the substrate, with connecting wires to link rectilinear segments, and a controlled machining angle to form a cavity, ensuring secure wire connections and minimizing tearing risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the machining depth is increased to ensure good contact between wire ends and module, then contact quality improves, but the risk of wire tearing increases

Engineering Contradiction:
Improvecontact qualityVSAvoidwire integrity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The wire is pre-formed into a zigzag configuration before machining, with connection portions extending beyond the substrate surface. This preliminary arrangement ensures that when machining occurs, the wire is already positioned to maintain integrity while enabling good contact, eliminating the need to choose between deep machining and wire protection

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The zigzag wire configuration acts as a cushioning mechanism where the detours provide mechanical compliance and stress distribution. The connection portions extending beyond the substrate serve as a buffer zone that absorbs machining stresses, preventing wire tearing while ensuring adequate contact depth

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

2Reliability

If the machining depth is reduced to prevent wire tearing, then wire integrity is maintained, but contact quality deteriorates

Engineering Contradiction:
Improvewire integrityVSAvoidcontact quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The wire is arranged in a zigzag pattern with connection portions extending in multiple directions beyond the substrate surface. This dimensional arrangement allows the wire to achieve good contact at shallower machining depths by utilizing the extended connection portions that protrude from the substrate, eliminating the need for deep machining

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If traditional straight wire configuration is used, then manufacturing is simpler, but wire tearing and poor contact occur due to machining tolerances

Engineering Contradiction:
Improvewire embedding simplicityVSAvoidconnectivity stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The wire is segmented into multiple portions: embedded portions within the substrate and connection portions extending beyond. The zigzag configuration creates distinct segments that can independently accommodate machining variations, with each connection portion serving as a separate contact point that maintains reliability despite tolerances

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The wire configuration changes from a simple straight line to a zigzag pattern with varying angles and extended connection portions. This parameter change in geometry provides mechanical compliance and stress distribution, allowing the wire to accommodate machining tolerances while maintaining both manufacturing feasibility and connectivity reliability

Inventive Principle:
Principle #35Parameter changes

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 approach enhances reliable electrical contact and resistance to wire tearing, improving the reliability and durability of electronic documents by reducing manufacturing tolerances and ensuring consistent connectivity.

Implementation Method 1

The wire is embedded in the substrate by means of ultrasonic vibrations transmitted to the wire from the tool. The vibrations are transmitted perpendicular to the substrate to embed the wire in the thickness of the substrate.

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 2

The wire is, for example, surrounded by an insulating sheath which is heated, for example for a very short time, to improve the adhesion of the sheath to the substrate.

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP4293569B1Inlay for an electronic document, method for producing an electronic document comprising such an inlay, and resulting electronic document
Publication Date: 2025.07.30 IDEMIA FRANCE SAS
  • EP4293569B1 patent drawingFigure 1
  • EP4293569B1 patent drawingFigure 2A~2D
  • EP4293569B1 patent drawingFigure 3~4

AI summary

An inlay (40) comprising a substrate (41) and a first zigzag portion (42) formed of a metal wire (421) embedded in an upper face (43) of the substrate (41), the first zigzag portion (42) comprising alternately straight segments (422) and curves (423), at least one of the straight segments (422) of the first zigzag portion (42) being disposed, at least in part, in an area (45) of the upper face (43) of the substrate (41) configured to form a counterbore in a cavity of an electronic document, and the inlay (40) comprising a connecting wire (47) configured to join together at least the straight segments (422) of the first zigzag portion (42). A method for manufacturing an electronic document (1) comprising such an inlay (40) and an electronic document (1).