Intaglio Ink with Transition Element IR Absorption
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Solution Overview
Problem
Current IR-absorbing materials for security documents, such as currency, face limitations in being either narrow-band, visible in the visible spectrum, or restricted to dark shades, making them incompatible with existing currency processing equipment and limiting design flexibility.
Innovation Solution
Development of an Intaglio printing ink using polymeric organic binders with transition element atoms or ions that absorb infrared radiation due to electronic transitions within their d-shells, allowing for broad-band IR absorption in the near-infrared range while being transparent in the visible and other infrared ranges, enabling secure and versatile security features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If narrow-band IR-absorbing materials are used, then machine-readable features can be detected by specialized equipment, but compatibility with standard currency processing equipment is lost
Solution Approach 1:
The patent changes the spectral absorption parameters of the IR material from narrow-band to broad-band characteristics. The ink composition absorbs IR radiation across a wide wavelength range (700-2500 nm), which allows standard silicon photodetectors in currency processing equipment to detect the features without requiring specialized narrow-band detection systems.
Solution Approach 2:
The broad-band IR-absorbing ink serves multiple functions: it provides machine-readable security features detectable by standard equipment, maintains visibility control through concealing layers, and ensures compatibility across different currency processing machines. This multi-functional approach eliminates the need for specialized equipment while maintaining security.
2Reliability
If IR-absorbing materials are used to create invisible security features, then security is enhanced, but the materials become visible in the visible spectrum requiring concealing layers
Solution Approach 1:
The patent applies local quality by creating specific zones with different IR absorption properties on the currency document. The IR-absorbing ink is applied only in specific security feature locations, while other areas remain transparent or have different properties. This allows the security features to be invisible to the naked eye while being detectable by IR sensors.
3Quantity of substance
If dark shades are used for IR-absorbing inks, then broad IR absorption is achieved, but design flexibility and visibility control are limited
Solution Approach 1:
The patent uses composite materials combining IR-absorbing pigments with transparent or lightly colored binders and concealing layers. This composite approach allows the ink to maintain broad IR absorption capacity while controlling visible appearance. The concealing layer acts as a composite structure that hides the dark IR-absorbing particles from visible light while allowing IR radiation to pass through or be absorbed as needed.
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 ink provides a broad-band IR-absorbing solution that is compatible with standard currency processing equipment, allowing for secure and invisible IR features on security documents, enhancing their authenticity and durability.
Implementation Method 1
infrared absorbing material comprising transition element atoms or ions whose infrared absorption is a consequence of electronic transitions within the d-shell of the transition element atoms or ions
Data Source
AI summary
Pasty ink for the engraved steel die printing process, having a viscosity value above 3 Pa·s, preferably above 5 Pa·s at 40° C., and comprising an infrared absorbing material, wherein said infrared absorbing material is a transition element compound whose IR-absorption is a consequence of electronic transitions within the d-shell of transition element atoms or ions.