Semi-Rigid Smart Card Case with Printed Circuit

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Solution Overview

Problem

Existing smart card cases for biometric cards are expensive, bulky, fragile, and complex due to the use of injection molded plastic, and their manufacturing process is lengthy and not eco-friendly.

Innovation Solution

A smart card case made of cellulosic fiber material with an electrical circuit deposited directly on it, connecting card contacts to a power supply interface, allowing for semi-rigid construction, reduced thickness, and recyclability, and enabling biometric data acquisition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If injection-molded plastic cases with metal connecting plates are used, then electrical connection and power supply are achieved, but manufacturing cost increases, device complexity increases, and manufacturing time increases

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidcase structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the electrical connection function directly into the plastic case structure by integrating conductive traces and contact pads during the injection-molding process. This eliminates the need for separate metal connecting plates and reduces assembly steps, thereby reducing device complexity while maintaining electrical connection reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses composite materials by combining conductive additives (such as carbon black, metal particles, or conductive polymers) within the plastic case material. This allows the case to simultaneously provide mechanical support and electrical connectivity, reducing the need for separate metal components and simplifying the overall structure.

Inventive Principle:
Principle #40Composite materials

2Reliability

If injection-molded plastic cases are used, then electrical connection is established, but the cases become too bulky and fragile

Engineering Contradiction:
Improveelectrical connection stabilityVSAvoidcase durability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent enhances the mechanical strength and durability of the plastic case by incorporating reinforcement materials such as fiberglass, carbon fiber, or nylon additives during the injection-molding process. This creates a composite plastic material that is both electrically conductive and mechanically robust, eliminating the fragility issue while maintaining electrical connection stability.

Inventive Principle:
Principle #40Composite materials

3Shape

If traditional plastic molding process is used, then case structure is formed, but manufacturing process becomes lengthy and expensive

Engineering Contradiction:
Improvecase structural formVSAvoidmanufacturing efficiency
Core Design Contradiction:
ShapeVSProductivity

Solution Approach 1:

The patent combines multiple functions (structural support, electrical connection, and power supply interface) into a single injection-molding process. The conductive traces and contact pads are formed directly during molding, eliminating subsequent assembly steps and reducing manufacturing time, thereby improving productivity while achieving the required case structure.

Inventive Principle:
Principle #5Merging (Combining)

4Shape

If hard brittle plastic is used, then case rigidity is achieved, but the case becomes too fragile to withstand impacts

Engineering Contradiction:
Improvecase rigidityVSAvoidimpact resistance
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent creates a composite material system by combining a flexible polymer matrix with conductive fillers and reinforcement additives. This composite structure provides both the required rigidity for case formation and the flexibility to absorb impact energy, preventing the case from being too fragile while maintaining structural integrity.

Inventive Principle:
Principle #40Composite 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 case is cost-effective, flexible, and resistant to shocks, facilitating efficient biometric data acquisition while simplifying the manufacturing process and using eco-friendly materials.

Implementation Method 1

an electrical circuit deposited directly onto the cellulose fiber material, which electrically connects electrical contacts of the card to a power supply interface

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3734493B1Case for enrolment for smart card
Publication Date: 2023.06.07 IDEMIA IDENTITY & SECURITY FRANCE SAS
  • EP3734493B1 patent drawingFigure 1~2
  • EP3734493B1 patent drawingFigure 3~4
  • EP3734493B1 patent drawingFigure 4a~5a

AI summary

The invention relates to a semi-rigid enrollment case for a smart card formed by folding and gluing a cardboard blank into a pocket the size of the card. The case includes an electrical circuit printed directly onto the cardboard on an internal surface. The circuit comprises contact pads connected to a power supply interface and arranged to connect the card's electrical contacts to the power supply interface when the card is inserted into the case. A biometric sensor on the card remains accessible to the user outside the case for enrollment. Through-holes are made in the cardboard on either side of lines of contact pads, creating independent flexible zones that provide improved contact between the pads and the card's electrical contacts.