Security Document Printing With Microlens Window Image Layering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for manufacturing security documents with optically imaging structures, such as those incorporating microlenses, struggle to create complex animations and machine-readable features that are both visually perceptible and secure.
Innovation Solution
A printing press is used to apply a multicolored image to a substrate with a surface pattern of color-receiving elements, transferring a periodic image element array using plano-convex microlenses that change the perceived image based on viewing angle, combined with machine-readable inks that react to non-visible electromagnetic radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional printing methods are used to manufacture security documents, then the manufacturing process is simple, but the ability to create complex animations and machine-readable features is limited
Solution Approach 1:
The printing press is divided into multiple independent printing units (first printing unit, second printing unit, third printing unit), each capable of applying different printing inks with specific properties. This segmentation allows each unit to specialize in creating specific features (machine-readable inks, optically variable inks, security features), thereby achieving complex functionality while maintaining modular device architecture
Solution Approach 2:
The printing press integrates multiple printing units that can apply different types of printing inks (machine-readable, optically variable, security) onto the same substrate. This multi-functionality enables a single device to create both machine-readable features and visually perceptible security features, resolving the contradiction between versatility and complexity
2Measurement precision
If machine-readable inks are applied to create security features, then machine readability is improved, but visual perception capability is reduced
Solution Approach 1:
Different regions of the substrate receive different types of printing inks with locally optimized properties. Machine-readable inks are applied in specific areas where machine readability is prioritized, while optically variable and security inks are applied in other areas where visual perception is prioritized. This local differentiation resolves the contradiction by allowing both machine readability and visual perception to excel in their respective zones
Solution Approach 2:
The security document incorporates multiple composite ink layers with different optical and magnetic properties. Machine-readable inks (with magnetic or conductive particles) are combined with optically variable inks and security inks in a composite structure, enabling the document to simultaneously provide machine-readable data and visually perceptible security features
3Reliability
If optically variable inks are used to create viewing angle-dependent images, then visual security is improved, but the ability to provide consistent machine-readable data is worsened
Solution Approach 1:
The printing process segments the substrate into distinct functional zones: one zone receives optically variable inks for visual security features that change with viewing angle, while another zone receives machine-readable inks with consistent magnetic or conductive properties. This spatial segmentation ensures that visual security and machine-readable consistency are not compromised by each other
Solution Approach 2:
Different local regions of the substrate are assigned different ink properties tailored to their specific function. The visual security region uses optically variable inks with angle-dependent optical properties, while the machine-readable region uses inks with stable magnetic or conductive properties. This local quality differentiation resolves the contradiction between visual security reliability and machine-readable data consistency
4Adaptability or versatility
If multiple printing inks are applied to create dynamic animations, then functionality is improved, but manufacturing complexity is worsened
Solution Approach 1:
The printing press is segmented into multiple specialized printing units, each configured to apply a specific type of printing ink (machine-readable, optically variable, security). This segmentation of the printing process into discrete, specialized stages enables the creation of dynamic animations with multiple ink layers while maintaining a manageable and modular device architecture
Solution Approach 2:
The printing press is designed as a multi-functional system that can apply various types of printing inks (machine-readable, optically variable, security) onto the same substrate in a single pass. This universal capability allows the creation of complex dynamic animations with multiple functional layers without requiring separate printing processes, thereby managing device complexity
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 enables the creation of security documents with dynamic animations and machine-readable features, enhancing security and functionality by allowing multiple images to be viewed from different angles and being readable with specialized inks.
Implementation Method 1
at least in the area of the transparent window on one side of the substrate a micro-optical structure consisting of microlenses is provided
Implementation Method 2
Machine-readable inks with which non-visible electromagnetic radiation interacts
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a printing machine for producing a security document (02). A counter printing cylinder (42) which guides a substrate (26) of the security document (02) and a transfer cylinder (43) which interacts with the counter printing cylinder (42) at a transfer location and which prints a printed image (27) onto the substrate (26) are provided, wherein the substrate (26) has at least one transparent window (04), and a micro-optical structure (03) consisting of microlenses (11) is provided on one face of the substrate (26) at least in the region of the transparent window (04) in question. The counter printing cylinder (42) and the transfer cylinder (43) are arranged so as to interact such that the micro-optical structure (03) consisting of microlenses (11) is arranged on one face of the substrate (26) at least in the region of the transparent window (04) in question and the at least one printed image (27) is arranged on the other substrate (26) face lying opposite the micro-optical structure (03) at least in the region of the transparent window (04). The printed image (27) in question has a plurality of image elements (28a to 28j) in a punctiform or linear pattern, each image element having a color which differs from white. A printing device is provided that applies a laminar expanded layer (39) which covers the printed image (27) in question onto at least one section of the printed image (27) in question on the printed image face facing away from the micro-optical structure (03). The printing device is designed as at least one inkjet print head (46) and is arranged downstream of the transfer point at which the transfer cylinder (43) prints the printed image (27) onto the substrate (26) being guided by the counter printing cylinder (42) on the same face of the substrate (26) as the printed image (27) produced at the transfer point, and the layer (39) formed by the at least one inkjet print head (46) consists of a lighter color than the color which differs from white and of which the printed image (27) in question consists.