Security Device with Varying Adhesive Strength for Terahertz Authentication
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Solution Overview
Problem
Current security devices for preventing forgery of securities lack an effective method to distinguish authentic from falsified articles using terahertz electromagnetic waves, as existing solutions do not provide a robust enough falsification-suppression effect.
Innovation Solution
A security device comprising a metallic layer with slits arranged in a specific pattern, an adhesive layer with varying adhesive strengths, and a concealing layer, which changes its terahertz wave transmission characteristics when peeled off, allowing for authenticity determination through terahertz wave analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional security mark is attached to securities, then forgery prevention is provided, but the mark can be easily removed or transferred by illegal attempts
Solution Approach 1:
The adhesive layer is designed with spatially varying adhesive strength, with a first region having lower adhesive strength and a second region having higher adhesive strength. This local differentiation ensures that when the security device is peeled off, part of the reflective layer remains on the article surface, creating a visible trace that prevents successful forgery while maintaining overall attachment reliability.
Solution Approach 2:
The security device incorporates a concealing layer that预先 conceals the pattern formed by the reflective layer. When an illegal removal attempt is made, the concealing layer is removed along with part of the reflective layer, preliminarily preventing the forger from completing the forgery by leaving a visible trace of the original security device.
2Reliability
If the adhesive strength is increased to prevent removal, then security is improved, but the device becomes difficult to remove legitimately and may damage the article
Solution Approach 1:
The adhesive layer has different adhesive strengths in different regions, allowing the security device to be easily removed from the first region while maintaining strong attachment in the second region. This enables legitimate removal without damage while still providing security through the trace left in the second region.
3Ease of manufacture
If a simple adhesive label is used, then ease of manufacture is improved, but falsification detection capability is insufficient
Solution Approach 1:
The security device uses a composite structure comprising a reflective layer, an adhesive layer with spatially varying adhesive strength, and a concealing layer. This composite structure maintains relative simplicity in manufacture while providing enhanced falsification detection capability through the combination of different material properties and their interactions during illegal removal attempts.
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 security device effectively suppresses falsification by altering its terahertz wave transmission spectrum when tampered with, enabling reliable authenticity verification without requiring complex equipment or long processing times.
Implementation Method 1
an anticounterfeit structure that exhibits a predetermined transmittance when terahertz electromagnetic waves of a specific frequency are applied
Implementation Method 2
In the authenticity determination method described in this document, terahertz electromagnetic waves are applied to the anticounterfeit structure, and the transmittance obtained thereby is compared with a reference value
Implementation Method 3
The adhesive layer includes a first portion in contact with a partial region of the main surface and a second portion in contact with another partial region of the main surface. The first portion has a lower adhesive strength to the anticounterfeit structure than that achieved by the second portion.
Implementation Method 4
JP 2000 309736 A discloses an infrared-absorbing ink composition containing a coloring material composed of tin-doped indium oxide powder which has a low absorption in the visible light region and has absorption in the infrared region.
Implementation Method 5
JP H06 297888 A discloses printing a barcode using a special fluorescent ink that is colorless when illuminated with visible light, and emits fluorescence when ultraviolet rays are applied.
Data Source
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AI summary
A security device that produces a falsification-suppression effect is provided. A security device (1) according to the present invention includes an anticounterfeit structure (10) including a metallic layer (13) with a plurality of slits (130), the anticounterfeit structure (10) having a transmittance peak resulting from resonance in the metallic layer (13), and an adhesive layer (20) provided on one main surface of the anticounterfeit structure (10) and including a first portion (21) in contact with a partial region of the main surface and a second portion (22) in contact with another partial region of the main surface, the first portion (21) achieving a lower adhesive strength to the anticounterfeit structure (10) than that achieved by the second portion (22).