Laser-Engraved Layer Structure for Angle-Dependent ID Photo Masking
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Solution Overview
Problem
Current security documents, particularly ID cards made of polycarbonate, face challenges in enhancing forgery-proofing of laser-engraved photos, as existing methods are vulnerable to counterfeiting and require additional aids for visual verification, and existing security features may introduce weak points that can be exploited for non-destructive opening of the composite.
Innovation Solution
A layer construction comprising a transparent radiation-engravable layer with colored or black engraving produced by laser radiation, combined with a nontransparent structural alteration that optically covers the engraving at specific viewing angles, creating a milky appearance and enhancing forgery-proofing without introducing weak points, achieved through a process involving focused nonionizing electromagnetic radiation and a coloring bath.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser engraving is used to create colored photos in transparent polycarbonate documents, then personalization and security features are enhanced, but the document becomes vulnerable to forgery attempts and the engraving is visible from both sides making verification difficult
Solution Approach 1:
The patent applies color changes by creating a colored or black engraving on one side of the transparent layer that appears invisible or milky from the opposite side. This is achieved through laser irradiation that modifies the optical properties of the polycarbonate material, causing light scattering that masks the engraving appearance from certain viewing angles while maintaining visibility from the engraving side.
Solution Approach 2:
The patent creates a composite structure within the transparent layer by combining the base polycarbonate material with laser-induced structural modifications. The laser irradiation creates a composite of modified and unmodified regions, where the modified regions have different optical properties (scattering centers) that create the angle-dependent visibility effect.
2Reliability
If transparent windows are used in ID documents, then security against mechanical forgery is improved, but the transparency may be destroyed and the document requires additional aids for verification
Solution Approach 1:
The patent uses color and transparency changes by creating regions with different optical properties through laser irradiation. The irradiated areas become opaque or milky while unirradiated areas remain transparent, creating a visual contrast that is visible without additional aids and maintains security functionality.
Solution Approach 2:
The patent applies local quality by creating spatially varying optical properties within the transparent layer. Different regions have different degrees of laser irradiation, resulting in areas with varying transparency and scattering properties. This allows the document to have both transparent and opaque features in specific locations, enabling verification without additional aids.
3Reliability
If additional security features are added to enhance forgery-proofing, then security level is improved, but weak points are introduced that can be exploited for non-destructive opening
Solution Approach 1:
The patent segments the security feature into two complementary parts: a colored or black engraving on one side and its optical complement (invisible or milky appearance) on the opposite side. This segmentation creates an interdependent security system where both sides work together to provide verification, and removing one side would destroy the security feature rather than allow non-destructive opening.
Solution Approach 2:
The patent merges the security function with the document structure by integrating the laser-engraved feature directly into the transparent polycarbonate layer. The security feature is not a separate adhesive layer or attachment but is formed within the material itself through laser irradiation, making it structurally integrated and resistant to non-destructive removal.
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 provides a high level of forgery-proofing by making the colored or black engraving invisible from certain angles, thereby enhancing the security of the document while maintaining transparency and preventing non-destructive opening, thus improving the overall security and authenticity verification of the document.
Implementation Method 1
colored or black engraving over part of the area that has been produced by means of nonionizing electromagnetic radiation (E)
Implementation Method 2
The nontransparent structural alteration optically covers the colored or black engraving over part of the area at a viewing angle within a range from 45° to 90°
Implementation Method 3
The nontransparent structural alteration optically covers the colored or black engraving over part of the area at a viewing angle within a range from 45° to 90°
Implementation Method 4
creating a milky appearance
Data Source
AI summary
The invention relates to a layer structure containing: (A) a first transparent radiation-engravable layer (A) with a first surface a1) and a second surface a2) which runs substantially parallel to the surface a1), said first layer (A) having a colorful or black part-engraving, said engraving being generated by means of nonionizing electromagnetic radiation (E), on the first surface a1) which forms a first outer surface of the layer structure; (B) optionally an additional transparent radiation-engravable layer (B) with a first surface b1) facing towards the first layer (A) and another surface b2) facing away from the first layer (A) and running substantially parallel to the surface b1); and (C) optionally at least one additional transparent plastic layer (C), wherein the additional layer (C) is selectively provided in one of a group of options consisting of: on the face of the first surface a1) of the layer (A), on the face of the additional surface b2) of the additional layer (B), between the two layers (A) and (B), or, in the event of additional layers (C), a combination of at least two of said options, and an image of the colorful or black part-engraving is located on the surface of the layer structure in the form of a nontransparent structural modification forming an additional outer surface of the layer structure and lying opposite the first surface a1). The invention likewise relates to the production of the layer structure as well as to a security document containing the layer structure according to the invention.