Security Feature Design with Variable Pitch Moiré Magnification
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Solution Overview
Problem
Existing micro-optic based security features that utilize moiré magnification struggle to achieve high degrees of apparent magnification without requiring high-resolution printing processes and precise angular alignment of microlens arrays, limiting their ability to create contrasting areas of magnification and depth across the security feature.
Innovation Solution
A method of designing a printed image with an array of optical elements by creating an icon matrix with varying matrix sizes within repeated sets, allowing for controlled mismatch between icon pitch and optical element pitch, independent of print resolution and rotational offset, enabling diverse magnification effects across different areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high degrees of apparent magnification are achieved using moiré magnification, then the magnification effect is improved, but high-resolution printing processes and precise angular alignment are required, increasing manufacturing complexity
Solution Approach 1:
The patent changes the pitch parameter of the optical element array relative to the icon array to achieve magnification. By deliberately creating a pitch mismatch between the optical elements and the printed icons, the system achieves moiré magnification without requiring high printing resolution or precise angular alignment. The pitch ratio becomes the key controlling parameter for magnification degree.
2Adaptability or versatility
If contrasting areas of magnification and depth are created across the security feature, then visual distinctiveness is improved, but the design flexibility is limited by the need for high-resolution printing and precise alignment
Solution Approach 1:
The patent applies different pitch ratios in different areas of the security feature to create contrasting magnification effects. By varying the pitch relationship between optical elements and icons in different regions, the design achieves local quality variations in magnification and depth perception without requiring high manufacturing precision throughout the entire feature.
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 allows for the creation of security features with varied magnification effects, enhancing visual distinctiveness and authenticity verification, while reducing the dependency on high-resolution printing and precise angular alignment, thus improving the security feature's effectiveness against counterfeiting.
Implementation Method 1
A moiré magnifier based security feature... when viewed through the two dimensional array of optical elements, one or more magnified versions of the icon is generated... Differences in the repeat length (pitch) of the icon and the lenses result in a mismatch which causes neighbouring lenses to magnify neighbouring parts of the icon
Data Source
AI summary
A method of designing at least an area of a printed image in a security feature is provided. The security feature comprises an array of optical elements overlaying the printed image. The method comprises designing an icon matrix comprising rows and columns of pixels having pixel values representing an icon to be viewed by a user of the security feature; determining a desired gap size to provide a desired magnification of the icon; generating an array of two dimensional matrices of pixels, wherein the array comprises a sequence of repeated sets of matrices, wherein each set comprises a first number of matrices of a first type having a first size and a second number of matrices of a second type having a second size, wherein the matrix of the first type and the matrix of the second type are based on the icon matrix, and wherein the first number, second number, first size, and second size are selected such that, the mean size of each matrix within the set deviates from the modal matrix size by the desired gap size. A printed image for a security feature is also provided.