Guilloche-Pixel Alignment for Identity Document Security

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Solution Overview

Problem

Conventional security patterns like guilloches on identity documents can degrade the quality and appearance of images, particularly when printed over image areas, reducing brightness and sharpness, and there is a need for improved security and image quality in such documents.

Innovation Solution

Incorporating a transparent layer with a pixel arrangement of sub-pixels of different colors and a guilloche pattern where the guilloche lines extend alongside the pixel lines, allowing for local opacification to enhance image quality and security by aligning with pixel lines, thus avoiding crossing and maintaining image clarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a guilloche pattern is printed on the document body, then security is improved, but image quality degrades when the guilloche crosses over image areas

Engineering Contradiction:
ImprovesecurityVSAvoidimage quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The document is divided into distinct functional zones: a first area containing the guilloche pattern for security purposes and a second area containing the image for visual information. By segmenting the document into these separate zones, the guilloche lines are prevented from crossing over the image area, thus maintaining image quality while preserving security features.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guilloche pattern is extracted from the image area and placed in a separate first area. This extraction removes the harmful interaction between the guilloche lines and the image, eliminating the degradation of image quality while keeping the security function intact in the dedicated guilloche area.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If guilloche lines are printed over image areas, then security coverage is improved, but brightness and sharpness of the image are reduced

Engineering Contradiction:
Improvesecurity coverageVSAvoidimage brightness
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The document surface is segmented into a first area for the guilloche pattern and a second area for the image. This spatial segmentation ensures that guilloche lines are confined to the first area and do not overlay the second area, preserving the brightness and sharpness of the image while maintaining security coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guilloche pattern is extracted from the image area and positioned in a separate first area. This extraction removes the guilloche lines from the image region, preventing them from blocking light and reducing image brightness, while the security function remains intact in the dedicated area.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If conventional guilloche printing is used, then security is provided, but the document can be easily falsified by replacing images

Engineering Contradiction:
ImprovesecurityVSAvoidfalsification detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The guilloche pattern and the image are merged into a single integrated design where the guilloche lines extend continuously across the document body. This merging creates a unified security feature that is difficult to replicate, as the guilloche pattern and image work together as a single authenticating element, making falsification detection easier.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Instead of placing the guilloche in a separate area from the image, the invention inverts the approach by extending the guilloche lines across the entire document body, including over the image area. This inversion creates a more robust security feature where the guilloche and image are integrated, making it harder for counterfeiters to replicate the authenticating combination.

Inventive Principle:
Principle #13The other way round (Inversion)

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

This approach improves the quality and security of identity documents by ensuring guilloche lines do not interfere with pixel lines, making it difficult to falsify the document and easier to identify counterfeit attempts, while maintaining image integrity.

Implementation Method 1

the transparent layer is capable of being locally opacified so as to at least partially block the passage of light in at least one region of the transparent layer

Methodology Applied
Scientific EffectLocal opacification:

Data Source

PatentEP3256330B1Identification document comprising a guilloche and and an arrangement of pixels
Publication Date: 2020.09.02 IDEMIA FRANCE SAS
  • EP3256330B1 patent drawingFigure 1~2
  • EP3256330B1 patent drawingFigure 3A~6
  • EP3256330B1 patent drawingFigure 7~9

AI summary

The invention relates to an identification document (30) comprising a transparent layer, an arrangement of pixels (19) facing the transparent layer, the sub-pixels being arranged in such a way as to form lines (LN) of sub-pixels in the arrangement (19) of pixels, and a guilloche (GL) in an area (Z2) adjacent to the arrangement (19) of pixels, the guilloche comprising at least one guilloche line (GL1, GL2), wherein the transparent layer can be locally opacified in order to obstruct the passage of the light, and wherein at least one guilloche line (GL1, GL2), so-called first line, extends in the continuation of a line of sub-pixels (LN), so-called second line, pertaining to the arrangement (19) of pixels, in such a way as to collectively form a single line.