Flexible Printed Circuit Contact Geometry Optimization

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Solution Overview

Problem

Current methods for manufacturing flexible printed circuits for smartcards are costly and do not fully meet the design requirements for electrical contacts, particularly in terms of geometry and surface area optimization.

Innovation Solution

A method involving a rolled band of flexible material divided into zones, where each zone undergoes metallization to form optimized rectangular electrical contacts connected to a common frame, with specific dimensions and geometry tailored to reduce surface area and ensure reliable adhesion and conductivity, using a reel-to-reel system and electro-deposition process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional manufacturing methods are used for flexible printed circuits, then the contacts can be formed, but the manufacturing cost is high and the contact geometry does not fully meet design requirements

Engineering Contradiction:
Improvemanufacturing costVSAvoidcontact geometry precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by optimizing the contact geometry with specific dimensions (2mm x 1.7mm rectangle) and controlling the summed surface area to be less than 127.01 mm². The metallization process parameters are adjusted to achieve the optimized contact shape that meets both cost and precision requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The flexible band is divided into multiple zones, with each zone containing a specific number of electrical contacts (at least five per zone). This segmentation allows for standardized manufacturing of contact patterns that can be consistently reproduced across the entire band, reducing manufacturing cost while maintaining geometric precision.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If the contact surface area is reduced to meet design requirements, then the manufacturing cost decreases, but the adhesion and conductivity may be compromised

Engineering Contradiction:
Improvemanufacturing costVSAvoidcontact adhesion and conductivity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent optimizes the contact parameters by defining specific dimensional requirements (2mm x 1.7mm rectangle) and controlling the total surface area to be less than 127.01 mm². These parameter changes achieve cost reduction while maintaining reliable adhesion and conductivity through the optimized geometry that balances surface area with electrical performance.

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

The method reduces manufacturing costs while ensuring good adhesion, conductivity, and longevity of the contacts, meeting the requirements for smartcard applications with optimized contact geometry and surface area.

Implementation Method 1

a reel-to-reel system and electro-deposition process

Methodology Applied
Scientific EffectElectro-deposition: Electrodeposition

Data Source

PatentEP2570007B1Method of manufacture of flexible printed circuits, flexible printed circuits, module and card
Publication Date: 2017.08.02 LINXENS HOLDING SAS
  • EP2570007B1 patent drawingFigure 1~4b
  • EP2570007B1 patent drawingFigure 3a
  • EP2570007B1 patent drawingFigure 4a~5

AI summary

A method of manufacture of flexible printed circuits having electrical contacts comprises: providing a rolled band (5) of a flexible material, unrolling the band so that zones are moved the one(s) after the other (s) through a metallization cell (4), forming on the band, 5 electrical contacts (9a- 9h) per zone. Each contact has a shape which encompasses a rectangle of length 2 millimetres (mm) and width 1.7 mm. A summed surface area of the contacts is less than 127.01 mm2.