Luminescent White Ink for True-Color Security Printing

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Solution Overview

Problem

Current security elements for data carriers, such as passports and branded items, face challenges in providing both high protection against counterfeiting and maintaining a visually appealing appearance, particularly in the stability and reproduction of true-color luminescence images under UV light.

Innovation Solution

Incorporating luminescent white alongside primary luminescent dyes like green, red, and blue to form a multicolored motif, where achromatic components are partially created by luminescent white, enhancing process stability, color representation, and flexibility, while allowing for dual UV excitation modes to reveal either a multicolored or grayscale image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional fluorescent inks are used for security printing, then the luminescent effect under UV light is achieved, but the color stability and true-color reproduction are insufficient

Engineering Contradiction:
Improveluminescent effect stabilityVSAvoidcolor reproduction accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent uses composite luminescent materials comprising multiple fluorescent pigments (yellow, orange, red, green, blue, violet) combined in specific ratios within ink formulations. This composite approach enables true-color luminescence by combining the emission spectra of individual pigments, achieving both stable luminescent effect and accurate color reproduction under UV excitation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent systematically varies the concentration ratios of different fluorescent pigments in the ink formulations to optimize color output. By adjusting pigment parameters (composition ratios, particle sizes, concentrations) and printing parameters (dot gains, screening frequencies), the invention achieves precise color control while maintaining luminescent stability.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If multiple luminescent pigments are combined to achieve true-color luminescence, then color representation is improved, but the printing process complexity increases

Engineering Contradiction:
Improvecolor representationVSAvoidprinting process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the luminescent ink system into six distinct pigment components (yellow, orange, red, green, blue, violet) that can be independently formulated and controlled. This segmentation allows each pigment to be optimized separately while maintaining overall color accuracy, and simplifies troubleshooting by isolating individual pigment contributions to the final luminescent output.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent develops a universal printing system that handles multiple luminescent pigments through standardized ink formulation procedures, printing press configurations, and quality control methods. The multi-functional approach allows the same printing infrastructure to produce various luminescent security features by simply changing ink formulations, rather than requiring dedicated equipment for each pigment type.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Quantity of substance

If luminescent white is used alongside primary luminescent colors, then the number of primary colors needed is reduced, but the printing process requires additional material management

Engineering Contradiction:
Improvenumber of primary colorsVSAvoidmaterial management
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent merges the function of luminescent white with the primary luminescent color system by integrating white pigment into the same ink formulation and printing process. This combination allows the white pigment to serve as both a background layer and a color-mixing component, reducing the need for separate white printing operations while maintaining material management efficiency through unified process control.

Inventive Principle:
Principle #5Merging (Combining)

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 significantly increases the stability of true-color luminescence printing, reduces the number of primary colors needed, enhances color representation, and provides a dual security feature with a grayscale image that can contain hidden information, making counterfeiting more detectable.

Implementation Method 1

The luminescence is preferably photoluminescence. Luminescence encompasses fluorescence and phosphorescence, including anti-Stokes luminescence.

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

Luminescence encompasses fluorescence and phosphorescence, including anti-Stokes luminescence.

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 3

Luminescence encompasses fluorescence and phosphorescence, including anti-Stokes luminescence.

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 4

Luminescence encompasses fluorescence and phosphorescence, including anti-Stokes luminescence.

Methodology Applied
Scientific EffectAnti-Stokes luminescence:

Data Source

PatentEP3452299B1Security element having a luminescent print
Publication Date: 2020.12.16 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP3452299B1 patent drawingFigure 1~2(b)
  • EP3452299B1 patent drawingFigure 3~4(b)
  • EP3452299B1 patent drawingFigure 5(a)~6

AI summary

The invention relates to a security element (12) for securing security papers, value documents, and other data carriers, comprising a luminescent print (14), which shows a multi-color motif in UV light. According to the invention, the luminescent print (14) is formed by luminescence white (20W) and at least two luminescence basic dyes, in particular from the group consisting of luminescence green (20G), luminescence red (20R), and luminescence blue (20B), and that the multi-color motif also contains achromatic portions (22) in colored areas, which achromatic portions are formed in the print (14) at least partially by means of luminescence white (20W).