Security Structure Diffractive Optical Element Microzone Integration
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Solution Overview
Problem
Existing security documents using diffractive optical elements lack versatility in substrate compatibility and are vulnerable to counterfeiting, as they require the entire document to be manufactured with the element, and the elements are not easily concealed to prevent unauthorized reproduction.
Innovation Solution
Incorporating non-opaque microzones with a cross-section of less than 1,000,000 µm², which are permeable to light and surrounded by an opaque periphery, allowing the diffractive optical elements to generate interference patterns while being difficult to detect without specific observation conditions, thereby enhancing security and making counterfeiting more challenging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diffractive optical elements are produced directly on documents by laser ablation, then the security element can be integrated into the document, but the entire document must be manufactured with the element present, reducing manufacturing flexibility
Solution Approach 1:
The patent separates the diffractive optical element from the document substrate, allowing the DOE to be manufactured independently on a separate substrate and then integrated into the document. This segmentation enables the DOE to be produced without requiring the entire document to be present during manufacturing, thereby improving substrate compatibility while maintaining security element integration.
2Measurement precision
If diffractive optical elements are made visible on documents, then they can be easily observed and verified, but they become easier to detect and replicate by counterfeitors
Solution Approach 1:
The patent applies local quality by making the diffractive optical element visible only under specific local conditions - when illuminated by a laser beam at particular angles. The DOE remains invisible under normal viewing conditions, but generates a visible interference pattern when subjected to the specific laser illumination geometry described in the patent. This resolves the contradiction by allowing verification when needed while maintaining concealment during normal use.
3Reliability
If non-opaque microzones are used to conceal diffractive optical elements, then counterfeiting becomes more difficult, but the elements are only visible under specific observation conditions
Solution Approach 1:
The patent employs preliminary action by pre-positioning the diffractive optical element within a non-opaque microzone during manufacturing. The element is concealed within this microzone until verification is needed, at which point laser illumination reveals the interference pattern. This preliminary placement ensures the element is ready for verification without requiring complex activation mechanisms, resolving the contradiction between security through concealment and ease of verification.
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 use of diffractive optical elements with various substrates without requiring the entire document's presence during manufacturing and increases security by making the elements harder to reproduce, as the non-opaque microzones are only visible under specific conditions, thus enhancing the document's authenticity verification process.
Implementation Method 1
at least one diffractive optical element generating at least one interference pattern in a viewing plane distant from the diffractive optical element
Implementation Method 2
an area sufficiently permeable to light to allow the visualization of the interference pattern thanks to the light passing through this area
Data Source
Figure 1~3
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Figure 9~13
AI summary
The present invention relates to a security structure (1) comprising: at least one non-opaque microzone (30), having a section no larger than 1,000,000 µm²; at least one diffractive optical element (40) generating at least one interference pattern (66) in a view plane (62) separated from the diffractive optical element (40), at least partially vertically adjacent to the non-opaque microzone (30).