Color Shifting Flake Mixture for Multi-Axis Security
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Solution Overview
Problem
Existing color shifting coatings lack the ability to exhibit distinct color shifts when viewed from different directions and fail to maintain the same color when observed at a normal angle, limiting their security and aesthetic applications.
Innovation Solution
A blend of magnetically alignable and non-magnetically alignable thin film interference flakes, where the flakes are oriented differently on a substrate, allowing for color shifts when tilted about specific axes and maintaining the same color at normal incidence, achieved by applying a magnetic field and carefully selecting goniochromatic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single type of color shifting flake is used in the coating, then the coating structure is simple, but the coating cannot exhibit distinct color shifts when viewed from different directions
Solution Approach 1:
The patent combines two different types of color shifting flakes (magnetic and non-magnetic) into a single coating composition. The magnetic flakes respond to magnetic fields while non-magnetic flakes remain randomly oriented, creating a unified coating that exhibits multi-directional color shifting capabilities without requiring separate coating layers
Solution Approach 2:
The coating uses a composite material system consisting of magnetic color shifting flakes, non-magnetic color shifting flakes, and a binder. This composite approach allows each flake type to contribute different orientational responses to magnetic fields, enabling the coating to display distinct colors when viewed from different directions while maintaining a single coating structure
2Adaptability or versatility
If magnetic flakes are aligned in a specific orientation, then the coating exhibits color shift when tilted, but the coating cannot maintain the same color when observed at normal angle
Solution Approach 1:
The patent applies different orientational characteristics to different flake types within the same coating. Magnetic flakes are aligned by magnetic fields to provide specific directional color shifts, while non-magnetic flakes maintain random orientations to stabilize the color appearance at normal incidence. This local differentiation of flake properties enables the coating to simultaneously achieve color stability at normal angles and color shifting when tilted
Solution Approach 2:
The patent utilizes changes in flake orientation parameters in response to magnetic field application. When a magnetic field is applied, magnetic flakes reorient themselves while non-magnetic flakes maintain their random distribution. This parameter change in flake orientation enables the coating to transition between stable color at normal incidence and color-shifting mode when tilted, without requiring precise control of each individual flake's orientation
3Reliability
If only non-magnetic flakes are used, then the coating is easy to manufacture, but the coating lacks security features with directional color shifts
Solution Approach 1:
The patent uses a magnetic field as an intermediary to align magnetic flakes during or after coating application. This intermediary approach allows the coating to be manufactured using standard application methods, with the magnetic alignment step providing the security feature. The magnetic field acts as a temporary mediator that organizes the magnetic flakes into oriented structures, creating directional color shift security features without requiring complex manufacturing processes
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 solution enables a coating that displays two distinct color shifts when tilted about different axes while appearing as the same color at normal angles, enhancing security and visual appeal in applications like banknotes and labels.
Implementation Method 1
a first plurality of magnetically alignable pigment flakes which exhibit a color shift from a first color to a second color with a change in viewing angle
Implementation Method 2
this invention relates primarily a color shift that occurs through thin film interference effects; that is, from multilayered thin film coatings having a reflector, a spacer and an absorber or a stack of interference layers
Data Source
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AI summary
Pigment flakes are blended together wherein some are magnetically alignable and exhibit a color shift from a first color to a second color with a change in viewing angle; and some are pigment flakes which exhibit a color shift from the first color to a third color or vice versa with a change in viewing angle, wherein the first, second and third colors are three different colors. The flakes are coated upon a substrate and magnetically alignable flakes are magnetically aligned. The non-magnetically alignable flakes are not aligned by the magnetic field and lie flat upon the substrate they are coated on. By judiciously selecting the angle upon which the magnetic flakes are oriented, an effect is created whereby an observer sees a color shift from a first color to a second or a first color to a third, when orienting the substrate by tilting it at different particular angles. The coated substrate can be used in security applications such as on currency or secure instruments.