Smart Card Wire Pad Design with Bridging Wires for Dense Contacts

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Solution Overview

Problem

The challenge in smart card design is to increase the density of connection pads without compromising their functionality, given the limited space and the need to comply with ISO/IEC standards, especially when integrating multiple I/O terminals.

Innovation Solution

A wire pad design featuring a bridging wire portion that maintains electrical connection among disconnected wire portions, allowing for a compact and high-density connection pad layout with varying wiring density and a spirally shaped routing pattern, optionally with a recess in the substrate to accommodate the bridging wire.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional wire pad designs are used with increasing number of I/O terminals, then the functionality of smart cards is improved, but the placement density of contact terminals deteriorates and becomes increasingly difficult to place without impairing proper functioning

Engineering Contradiction:
ImprovefunctionalityVSAvoidplacement density
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The wire pad is segmented into multiple wire portions (first wire portion, second wire portion, third wire portion) that can be independently routed and connected to different I/O terminals. This segmentation allows each wire portion to be optimally positioned and routed to its respective terminal, enabling higher placement density while maintaining proper functioning of each contact terminal.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the density of connection pads is increased to utilize limited card space, then the productivity and functionality are improved, but the reliability of electrical contact may deteriorate

Engineering Contradiction:
Improvedensity of connection padsVSAvoidelectrical contact
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Different wire portions are routed through different regions of the card body substrate, allowing each wire portion to have optimal local routing characteristics. The first wire portion is routed through a first region, the second wire portion through a second region, and the third wire portion through a third region, ensuring that each connection maintains reliable electrical contact despite the high overall density of connection pads.

Inventive Principle:
Principle #3Local quality

3Area of stationary object

If wire portions are routed densely to achieve high connection pad density, then the area utilization is improved, but the risk of disconnection during module integration increases

Engineering Contradiction:
Improvearea utilizationVSAvoidelectrical connection
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The wire portions are routed through different spatial dimensions and regions of the card body substrate. The first wire portion extends in a first direction through a first region, the second wire portion extends in a second direction through a second region, and the third wire portion extends in a third direction through a third region. This multi-dimensional routing strategy distributes the electrical connection paths across different spatial domains, reducing the risk that dense routing in a single plane will cause disconnections during module integration.

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

Data Source

PatentEP4392895B1Wire pad design of a connection pad in a prelam body of a smart card, prelam body, smart card, method of forming a wire pad design, and method of forming a smart card
Publication Date: 2025.07.02 LINXENS HOLDING SAS
  • EP4392895B1 patent drawingFigure 1~2
  • EP4392895B1 patent drawingFigure 3
  • EP4392895B1 patent drawingFigure 4~5

AI summary

In aspects, the present invention relates to a wire pad design of a connection pad in a prelam body of a smart card, to a prelam body with at least one such connection pad em- bedded into a substrate, to a smart card comprising such a prelam body, to a method of forming a wire pad design of a connection pad of a prelam body of a smart card, and to a method of forming a smart card. In some illustrative embodiments, a wire pad design of a connection pad in a prelam body of a smart card is provided, the wire pad design comprising a connection pad wiring pattern formed by plural wire portions extending in a contacting pad plane, and a bridging wire portion which at least partially extends outside the contacting pad plane. The bridging wire portion electrically and mechanically connects at least some of the plural wire portions with each other.