Dynamic Color-Changing Pigment Particles for Anti-Counterfeiting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing authentication systems using UV light for security features only produce static emission spectra, lacking dynamic color-changing properties that can be used to authenticate or identify objects effectively.
Innovation Solution
Development of pigment particles with a core and shell structure, where the core contains a fluorescent material and the shell is made of a photochromic material that changes optical properties under UV illumination, causing a dynamic color change from a first appearance to a second appearance over a period of time, allowing for the creation of dynamic, reversible color-changing effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If UV light is used to activate visible effects through fluorescence, then authentication can be performed, but the emission spectrum remains static and lacks dynamic color-changing properties
Solution Approach 1:
The patent combines fluorescent material and photochromic material into a single integrated pigment particle structure. The fluorescent core provides the base emission spectrum while the photochromic shell dynamically modifies the spectrum in response to UV illumination, creating a multi-functional authentication feature that evolves over time.
Solution Approach 2:
The photochromic material in the shell dynamically changes its optical properties when exposed to UV light, transitioning between different absorption states. This causes the emission spectrum to evolve from an initial state to a final state, providing dynamic color-changing authentication that is not possible with static fluorescent materials alone.
2Adaptability or versatility
If photochromic material is used to change absorption spectrum under UV light, then dynamic color change is achieved, but the system becomes more complex compared to simple fluorescent materials
Solution Approach 1:
The patent employs a nested structure where the photochromic material shell surrounds the fluorescent material core. This concentric arrangement allows both materials to work together synergistically: the fluorescent core provides continuous emission while the photochromic shell dynamically modulates the spectrum, achieving complex functionality through a relatively simple structural arrangement.
3Adaptability or versatility
If the photochromic shell completely blocks UV light to attenuate fluorescent emission, then dynamic color change is achieved, but the fluorescent material cannot continuously emit radiation
Solution Approach 1:
The photochromic shell is designed with specific local optical properties that allow selective transmission and absorption of different wavelengths. The shell's optical density and thickness are optimized to attenuate specific portions of the fluorescent spectrum while maintaining sufficient UV transmission to sustain the fluorescent core's emission, achieving balanced dynamic modulation.
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
Enables the creation of unique, dynamic color-changing features that can be used for authentication and identification, providing enhanced security and attention-grabbing effects on documents and products, distinguishing them from static UV-induced features.
Implementation Method 1
the core contains a fluorescent material... the first appearance is a first color based in part upon the fluorescent emissions from the fluorescent chromophore
Implementation Method 2
the shell includes a photochromic material which has a first optical property when illuminated by a first light source and a second optical property when illuminated by a second light source... the photochromic material changes from the first optical property to the second optical property
Implementation Method 3
the second optical property attenuates an emitted radiation from the fluorescent material... the photochromic material which has a second optical property... which attenuates an emitted radiation from the fluorescent material
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Methods and systems for creating optical effects in pigments, inks, and on media are described. There is in particular described a system or indicia for use as a security or identification feature comprising a combination of material that is capable of inducing a change of optical appearance of the system or indicia in response to exposure to ultraviolet (UV) light. The combination of materials includes at least a first material that changes its optical appearance under exposure to UV light and a second material that provides a color under ambient visible light or under exposure to UV light. The first and second materials are selected in such a way that exposure to UV light causes a visible spectrum of the system or indicia to dynamically shift over time from a first spectrum to a second spectrum distinct from the first spectrum