Security Sheet Windows and Laser Fusing for Identity Documents

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Solution Overview

Problem

The existing methods for manufacturing plastic security sheets for identity documents are time inefficient and can result in uneven fusing due to temperature and pressure distribution issues during the heating and cooling process, leading to potential quality inconsistencies and vulnerabilities to counterfeiting.

Innovation Solution

A security sheet with a plastic substrate comprising a plurality of windows formed by inserts in apertures within the layers, combined with a laminating process using continuous belts for heating and cooling, ensuring uniform quality and enhanced security features like opaque regions and machine-readable zones to prevent data alteration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional batch heating and cooling method is used, then plastic layers can be fused together, but production time is long (around thirty minutes per cycle) and quality is uneven due to temperature and pressure distribution issues

Engineering Contradiction:
Improveuniformity of fusingVSAvoidproduction time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent replaces the traditional mechanical batch heating and cooling system with a laser-based system. The laser provides localized, precise heating that can be controlled independently for each plastic layer, eliminating the need for large-scale thermal fields that cause uneven temperature distribution. This substitution of heating mechanism directly resolves both the uniformity and time efficiency problems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the heating parameters from broad, low-temperature batch heating to focused, high-temperature laser heating. By concentrating energy in specific locations and controlling the heating duration precisely, the system achieves uniform fusing quality while reducing the overall processing time from thirty minutes to a much shorter duration.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If traditional batch heating and cooling method is used, then plastic layers can be fused together, but the quality is uneven due to varying temperature and pressure distribution throughout the stack

Engineering Contradiction:
Improveuniformity of fusingVSAvoidquality consistency
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent replaces the traditional mechanical batch heating and cooling system with a laser-based system. The laser provides localized, precise heating that can be controlled independently for each plastic layer, eliminating the need for large-scale thermal fields that cause uneven temperature distribution. This substitution of heating mechanism directly resolves both the uniformity and time efficiency problems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent applies heating locally to each plastic layer using a movable laser beam rather than heating the entire stack uniformly. The laser can be positioned at different locations and adjusted in intensity, allowing each layer to receive precisely the heat it needs for optimal fusing. This local control eliminates the temperature gradients that cause quality inconsistencies in batch processing.

Inventive Principle:
Principle #3Local quality

3Reliability

If plastic security sheets are manufactured with windows, then security features are enhanced, but counterfeiters can still grind away the plastic substrate to alter personal data

Engineering Contradiction:
Improvesecurity against counterfeitingVSAvoidvulnerability to data alteration
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent embeds security threads within the plastic substrate at the window locations. These threads are made of materials that are difficult to remove or alter without damaging the surrounding plastic. The combination of plastic and embedded thread creates a composite structure that maintains security even when the plastic is subjected to grinding or other alteration attempts, as the threads serve as a visible and structural deterrent.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent pre-embeds security threads in the plastic substrate during manufacturing, creating a preventive measure against future counterfeiting attempts. The threads are positioned strategically at window locations where personal data appears, creating a barrier that makes data alteration detectable and difficult before any grinding or tampering occurs.

Inventive Principle:
Principle #9Preliminary anti-action

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 solution significantly reduces production time, ensures uniform quality, and enhances security by making it difficult for counterfeiters to alter personal data without damaging the windows, thereby increasing the document's authenticity and security.

Implementation Method 1

the layers are heated and pressed together under pressure by the heating devices such that they fuse into a plastic sheet

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

the continuous belts move the section to between the cooling devices where it is cooled and pressure is again applied

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP3359391B1A security sheet for an identity document
Publication Date: 2020.12.16 DE LA RUE INTERNATIONAL LTD
  • EP3359391B1 patent drawingFigure 1~2
  • EP3359391B1 patent drawingFigure 3~4
  • EP3359391B1 patent drawingFigure 5~6

AI summary

The present disclosure provides a security sheet (11) for an identity document (10). The security sheet (11) comprises a plastic substrate (14) formed from a plurality of plastic layers (34). The plastic substrate (14) comprises a plurality of windows (60) and each window (60) has a maximum width in the range of from approximately 0.5 mm to approximately 10 mm. The present invention is further directed to an identification document (10) comprising the security sheet (11), a plurality of such identity documents (10) and a method of manufacturing the security sheet (11).