Angled Slot Design for Chip Card Metallic Core Stability

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Solution Overview

Problem

The existing card bodies with metallic cores and dual interface functionality suffer from instability and potential damage due to the slot cut in the metal, which also leads to a degraded appearance and risk of short circuits.

Innovation Solution

A method for producing a card body with a metallic base body featuring a slot that is formed at an angle other than 90 degrees to the main surface, providing overlap between regions separated by the slot and preventing shearing movement, while also allowing for adhesive filling to enhance stability and appearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a slot is formed perpendicular (90 degrees) to the main surface of the metallic base body, then the dual interface functionality is achieved through proper magnetic/current flow redirection, but the card body becomes unstable and prone to shear forces near the module opening

Engineering Contradiction:
Improvedual interface functionalityVSAvoidcard body stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The slot is formed with an entry angle that is not equal to 90 degrees relative to the main surface, creating an asymmetric configuration. This asymmetric slot design prevents shearing movement between the two regions of the metallic base body while still maintaining the dual interface functionality through proper magnetic flow redirection in the angled metal surfaces.

Inventive Principle:
Principle #4Asymmetry

2Reliability

If a perpendicular slot is formed in the metallic base body, then the slot prevents short-circuit current, but plastic films sag in the slot area during lamination leading to degraded appearance

Engineering Contradiction:
Improveshort circuit preventionVSAvoidappearance quality
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The asymmetric slot configuration with non-90 degree entry angle provides structural support that prevents plastic films from sagging into the slot area during lamination, while still maintaining the electrical isolation function to prevent short-circuit currents between metal regions.

Inventive Principle:
Principle #4Asymmetry

3Reliability

If a perpendicular slot is formed in the metallic base body, then the slot prevents short-circuit current, but the slot becomes clearly visible through protective varnish making the appearance impaired

Engineering Contradiction:
Improveshort circuit preventionVSAvoidvisual appearance
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The angled slot configuration reduces its visual prominence when viewed from above, as the oblique entry angle creates a less noticeable feature compared to a perpendicular cut. The slot remains functional for preventing short-circuit currents while being less visually intrusive under protective varnish coatings.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP4264488B1Method for producing a card body, card body for a chip card, and chip card
Publication Date: 2025.06.18 GIESECKE & DEVRIENT EPAYMENTS GMBH
  • EP4264488B1 patent drawingFigure 1~3
  • EP4264488B1 patent drawingFigure 4~6
  • EP4264488B1 patent drawingFigure 7~10

AI summary

The invention relates to a method for producing a card body (10) for a chip card (30), having the steps of: - providing (100) a metal main part (11) with two main surfaces (12, 13) lying opposite each other and a peripheral surface (14) which connects the two main surfaces (12, 13), wherein a module opening (17) for receiving a chip module (30) is already produced in the main part (11) or is to be produced in a module opening zone, and - producing (200) a slot (18) on the peripheral surface (14) between the two main surfaces (12, 13), wherein the slot (18) is formed from the peripheral surface (14) to the module opening (17) or to the module opening zone, and an insert angle (α) of the slot (18) in at least one of the two main surfaces (12) is an unequal to 90° relative to the main surface (12).