Optical Effect Layer Curing via Inverted Photomask Geometry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing processes for producing optical effect layers (OELs) using photomasks often result in shadow effects due to the geometry of the radiation source and photomask, limiting their flexibility and effectiveness in creating motifs with multiple patterns from a single cured layer.
Innovation Solution
A process involving a radiation curable coating composition with magnetic or magnetizable pigment particles, where the coating layer is exposed to magnetic fields and cured through a photomask in direct contact with the substrate, using multiple magnetic-field-generating devices and irradiation sources to orient and fix the particles in specific patterns without shadow effects, allowing for the creation of optical effect layers with multiple patterns from a single cured layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a photomask is used to cure the coating layer through the substrate, then patterned optical effect layers can be produced, but shadow effects occur due to the geometry of the radiation source and photomask
Solution Approach 1:
The patent inverts the conventional curing approach by applying the radiation source from the substrate side rather than the coating side. This allows the photomask to be positioned between the radiation source and the coating layer, enabling UV light to pass through the photomask windows and cure the coating material in the desired pattern areas without creating shadow effects that would compromise pattern clarity.
Solution Approach 2:
The substrate acts as an intermediary medium that allows UV radiation to pass through from the radiation source to the photomask and then to the coating layer. The substrate's transparency to UV wavelengths enables this indirect curing path, eliminating the shadow effects that would occur with direct top-down curing while still achieving precise pattern formation.
2Adaptability or versatility
If multiple magnetic-field-generating devices are used to create complex patterns, then design flexibility is improved, but device complexity increases
Solution Approach 1:
Each magnetic-field-generating device is designed to perform multiple functions: creating specific magnetic field patterns, orienting pigment particles in desired configurations, and defining pattern boundaries. The devices can be programmed or configured to produce different field distributions, allowing a single device to create multiple pattern types (text, logos, geometric shapes) without requiring separate specialized equipment for each pattern design.
Solution Approach 2:
The patent employs magnetic-field-generating devices with adjustable parameters such as field strength, frequency, and spatial distribution. By changing these parameters, the same physical device can create diverse magnetic field configurations that result in different pigment particle orientations and pattern formations, thereby achieving design flexibility without increasing the number of physical devices.
3Manufacturing precision
If the photomask is placed in direct contact with the substrate, then shadow effects are avoided, but the curing process becomes more sensitive to substrate properties
Solution Approach 1:
The patent addresses substrate sensitivity by adjusting the UV radiation wavelength parameters to match the transmission characteristics of different substrate materials. By selecting radiation wavelengths that optimally penetrate the specific substrate type being used, the process maintains consistent curing effectiveness across various substrates while preserving the direct-contact photomask configuration that eliminates shadow effects.
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 enables the production of optical effect layers with improved pattern clarity and flexibility, avoiding shadow effects and allowing for the creation of complex designs like rolling bar features, enhancing their use in security documents and decorative applications.
Implementation Method 1
curing through the substrate (x50) and through one or more windows (x20) of a photomask (x00) the coating layer (x40) to a second state so as to fix the magnetic or magnetizable pigment particles in their adopted positions and orientations, wherein the at least partially curing is carried out by irradiation with a first irradiation source (x30)
Implementation Method 2
exposing the coating layer (x40) to the magnetic field of a first magnetic-field-generating device (x81) thereby orienting at least part of the magnetic or magnetizable pigment particles
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
The present invention relates to the field of printing devices and processes for producing optical effect layers (OEL) comprising magnetically oriented magnetic or magnetizable pigment particles on a substrate. In particular, the present invention relates to printing devices and processes for producing said OELs as anti-counterfeit means on security documents or security articles or for decorative purposes.