Tamper-Evident Security Device Using Moire Fringe Optical Alignment
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Solution Overview
Problem
Existing anti-counterfeit and tamper-evident technologies face challenges in effectively distinguishing between authentic and counterfeit products, as well as detecting tampering, particularly since optically variable features can be reattached without visible damage, making them unreliable for ensuring product integrity.
Innovation Solution
A security device featuring an optically transparent layer with a repeating array of lenticular lenses and image elements, where the pitch ratio between the lenses and image elements differs by a small absolute value, creating a distinctive 3D effect through Moire fringes that changes with viewing angle, which is destroyed upon tampering, thereby indicating authenticity or tampering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optically variable features such as holograms are used on packaging seals, then anti-counterfeiting capability is improved, but the seal can be carefully removed and reattached without visible damage, compromising tamper-proofing reliability
Solution Approach 1:
The security device is divided into two separate parts: a first part with an array of optical focusing elements and a second part with an array of image elements. These parts are held together by a release layer that allows controlled separation. When tampering occurs, the parts can be separated to reveal evidence, while the precise alignment requirements make reattachment without visible damage impractical.
Solution Approach 2:
The patent replaces traditional mechanical sealing methods with an optical alignment-based security feature. The tamper-evident mechanism relies on the optical relationship between two arrays (focusing elements and image elements) rather than mechanical interlocking, allowing for more sophisticated detection of tampering through optical misalignment.
2Reliability
If a break-away component is used on product packaging, then tamper-evident capability is improved, but the component cannot be re-attached, reducing versatility
Solution Approach 1:
The release layer provides dynamic control over the relationship between the two parts. It allows the parts to be separated when tampering is detected, while also enabling controlled reattachment for legitimate purposes. This dynamic behavior distinguishes it from static break-away components that permanently fail upon first separation.
3Strength
If packaging is glued shut with strong adhesive, then sealing strength is improved, but tampering causes noticeable distortion or fracture, reducing ease of operation
Solution Approach 1:
The release layer acts as an intermediary between the two parts of the security device. It provides controlled adhesion that is sufficient to maintain sealing strength during normal use, but allows for controlled separation when tampering is needed, without causing damage to either part.
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 device provides a reliable visual authentication method that is difficult to replicate, offering a clear indication of tampering or authenticity through a distinctive 3D optical effect that is lost when the device is separated, preventing reattachment and ensuring product integrity.
Implementation Method 1
an array of lenticular lenses arranged collectively to permit viewing of a particular part of the whole image provided by the second part, at a first viewing angle
Implementation Method 2
Moire fringes are visibly present, as discussed herein
Data Source
AI summary
A security device (1) comprising an optically transparent layer (3) including a repeating first array of separate optical focussing elements (3) (e.g. having translational symmetry) wherein a pitch distance between repeated elements in the first array is a first pitch value (A). The device also includes a repeating second array of separate image elements (6) (e.g. having translational symmetry) collectively defining an image viewable through the first part. The device is structured such that a pitch distance between repeated or successive elements in the second array is a second pitch value (B) wherein the ratio (A/B) of the first pitch value and the second pitch value has a value, A/B=n±Δ, that differs from a positive integer value, n, according to an absolute difference, Δ, not exceeding 0.01 and not less than 0.001.