Card Security Element with Oblique Cylindrical Lenses
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Solution Overview
Problem
Existing card-shaped data carriers lack security elements that provide conspicuous optical effects when tilted, offering limited design freedom and high production complexity, especially in creating three-dimensional and movable image effects.
Innovation Solution
A security element with a cylindrical viewing grid and a printed motif image, constructed using a modulo algorithm, allowing for individualized and high-resolution display of complex images with depth and movement effects, utilizing cylindrical lenses and an optical spacer layer, which can be easily integrated into card-shaped data carriers with enhanced thickness for reduced production demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional embossed holograms or hologram-like diffraction structures are used as security elements, then protection against unauthorized reproduction is improved, but the mechanical stability of the card body is reduced due to folding or buckling requirements
Solution Approach 1:
The security element is divided into a first security feature (optically diffractive microstructures for anti-reproduction protection) and a second security feature (moiré magnification arrangement with cylindrical lenses for visual effects), allowing each segment to fulfill its specific function without compromising the other or the card's mechanical stability
Solution Approach 2:
The patent changes the optical parameters by using cylindrical lenses with specific focal lengths and pitch distances, combined with printed motif images at controlled distances, to create moiré magnification effects that provide visual security without requiring the card body to be foldable or bucklable
2Illumination intensity
If moiré magnification arrangements with spherical microlenses are used, then optical effects when tilted are improved, but the design freedom for displayed motifs is limited
Solution Approach 1:
The patent uses cylindrical lenses instead of spherical microlenses, changing the curvature geometry from spherical to cylindrical. This allows the security element to maintain optical effects when tilted while providing greater design freedom for displayed motifs, as the cylindrical geometry can be combined with various printed motif images at different distances and orientations
3Ease of manufacture
If lenticular grids with printed images are incorporated during manufacturing, then production ease is improved, but the ability to customize individual images is lost
Solution Approach 1:
The patent creates a dynamic security element where the displayed image can change based on the tilting direction and angle. The moiré magnification arrangement with cylindrical lenses allows different portions of the printed motif image to be magnified and displayed depending on the viewing angle, providing both production ease and effective customization through optical dynamics
4Manufacturing precision
If high-resolution target images are displayed with three-dimensional and movable effects, then security feature conspicuity is improved, but production complexity increases
Solution Approach 1:
The patent introduces an optical spacer layer as an intermediary element between the cylindrical lens array and the printed motif image. This spacer layer at a controlled distance (e.g., 0.5-2 mm) enables the moiré magnification effect that creates high-resolution three-dimensional and movable image effects while simplifying the manufacturing process by allowing standard printing techniques to be used for the motif image
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 a striking combination of three-dimensional and movable image effects when tilted, reducing production complexity and costs while maintaining mechanical stability, and allowing for additional hidden information and personalization through laser-writable layers.
Implementation Method 1
a cylindrical viewing grid from a plurality of periodically arranged, cylindrical viewing elements each having parallel cylinder axes for reconstructing the target image when viewing the motif image using the viewing grid
Implementation Method 2
The use of a moiré magnification arrangement as a security feature is known from US Pat. No. 5,712,731 A. The security device described there has a regular arrangement of essentially identical, printed microimages with a size of up to 250 μm, as well as a regular two-dimensional arrangement of essentially identical spherical microlenses.
Data Source
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AI summary
The invention relates to a security element for incorporation in a card-type data carrier, having a raster image arrangement for representing a prespecified image given by an image function f(x,y), having a printed motif image which is subdivided into a plurality of cells in which in each case imaged regions of the prespecified image are arranged, and having a cylindrical viewing raster composed of a plurality of periodically arranged, cylindrical viewing elements, e.g. cylinder lenses, having in each case mutually parallel cylinder axes for reconstructing the prespecified image when viewing the motif image using the viewing raster, wherein the viewing raster and the motif image are arranged at a predetermined distance from each other. The cylinder axis of the cylinder lenses do not extend parallel to the edges of the card-type data carrier, but oblique thereto. A laser-readable layer is provided. Said motif image can be printed with offset printing, intaglio printing, relief printing, screen printing or using digital printing methods such as inkjet printing or laser printing and preferably using the Toray dry offset method