Color Laser Image Personalization Shadow Elimination

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Solution Overview

Problem

Existing methods for forming color laser images in identity documents suffer from reduced image quality due to shadow effects caused by non-reflecting black surfaces forming gray levels either on or above the subpixels, which darken the final personalized image.

Innovation Solution

A method involving a transparent protection layer, a printed latent image with color subpixels and non-colored surfaces, a laserable layer, and a laser beam that forms gray levels in the laserable layer under the latent image, with calculated energy deposition and area variation to create proportional blackening, improving image quality by adjusting laser energy based on subpixel and non-colored zone characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If non-reflecting black surfaces are formed on or above the subpixels to create gray levels, then the personalized image can be formed, but shadow effects occur that darken the final image and reduce quality

Engineering Contradiction:

Improveimage qualityVSAvoidshadow effects

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent inverts the conventional approach by forming the non-reflecting black surfaces underneath the latent image rather than on or above it. The laser beam carbonizes the laserable layer from below, creating gray levels that do not cast shadows on the color subpixels, thereby eliminating the shadow effects that darken the image while still achieving the desired gray level personalization.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent moves the gray level formation to a different spatial dimension by placing the laserable layer beneath the latent image. This dimensional repositioning allows the carbonized surfaces to generate gray levels without physically obstructing or casting shadows on the color subpixels, resolving the contradiction between image formation and shadow elimination.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If the personalized image is made highly reflective to be observable in ambient light, then visibility is improved, but the shadow effects from black surfaces still darken the image

Engineering Contradiction:

Improveimage reflectivityVSAvoidshadow effects

Core Design Contradiction:

Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent inverts the structure so that reflective surfaces and color subpixels are positioned above the carbonized gray level surfaces. This inversion allows the image to maintain high reflectivity for ambient light observation while the shadow-casting black surfaces are relocated underneath, eliminating their harmful shadow effects on the visible image.

Inventive Principle:

Principle #13The other way round (Inversion)

3Manufacturing precision

If laser energy is increased to create darker gray levels, then image contrast is improved, but shadow effects are intensified and image quality deteriorates

Engineering Contradiction:

Improveimage contrastVSAvoidshadow effects

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent resolves this contradiction by inverting the spatial relationship between gray level surfaces and color subpixels. Higher laser energy can now be used to create darker gray levels and improve image contrast without intensifying shadow effects, because the carbonized surfaces are positioned underneath and do not cast shadows on the color subpixels.

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 enhances the quality of the personalized image by minimizing shadow effects and increasing reflectivity, allowing for clearer visualization of the image in ambient light without additional light sources, while maintaining compatibility with existing materials and processes.

Implementation Method 1

a laser beam that passes through the protection layer, through the subpixels of the latent image, and the non-colored surfaces and forms the gray levels of a final personalized image in the laserable layer

Methodology Applied

Scientific EffectLaser carbonization: Laser Ablation

Implementation Method 2

The gray levels that lead to the latent image being personalized in order to form the final image are calculated with the help of software that takes an original image, segments it into subpixels, calculates the corresponding color shades, and determines the gray levels that are to be carbonized in the laserable layer

Methodology Applied

Scientific EffectCarbonization: Pyrolysis

Implementation Method 3

the assembly being laminated on a medium

Methodology Applied

Scientific EffectLamination: Lamination

Data Source

PatentUS10112429B2Method of forming a color laser image, and resulting document

Publication Date: 2018.10.30 IDEMIA IDENTITY & SECURITY FRANCE SAS

AI summary

The present invention relates to a method of forming color laser images. The latent image made up or color subpixels (2) and of non-colored zones is personalized by a laser beam (8) that acts in the laserable layer (3) situated under the color subpixels (2) and the non-colored zones to cause a final personalized color laser image to appear. The invention is applicable to identity documents.