Lenticular Security Element Laser Demetallization
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Solution Overview
Problem
Existing methods for producing security elements with lenticular pattern images are inefficient due to high costs and low production speed, particularly in industrial settings, as they require expensive scanning devices and separate masks for each design, limiting the ability to achieve high-speed demetallization of metallic layers.
Innovation Solution
A method utilizing a lenticular pattern with microlenses and a metallic motif layer, where pulsed laser radiation is shaped by a beam shaper or switchable mask to simultaneously demetallize multiple areas, allowing for high-speed production of security elements with angle-dependent visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If direct laser inscription scanning is used to demetallize the metallic motif layer, then precise demetallization patterns can be achieved, but production speed becomes too slow for industrial applications
Solution Approach 1:
The invention segments the laser beam into multiple parallel beams using a beam splitter, allowing simultaneous demetallization of multiple areas. Instead of scanning one beam sequentially across the metallic layer, the laser beam is divided into N beams that strike different locations at once, achieving both precision and high-speed production.
Solution Approach 2:
The invention combines multiple laser beams into a single source and merges their demetallization effects on the metallic motif layer. By using a beam splitter to create multiple beams from one laser source, the system achieves the precision of individual beam control with the productivity of parallel processing.
2Adaptability or versatility
If separate masks are used for each design in laser impingement, then design-specific demetallization can be achieved, but device complexity and production time increase due to mask changes
Solution Approach 1:
The invention replaces static masks with dynamic, programmable spatial light modulators that can change the beam pattern electronically. This allows different demetallization designs to be achieved by software control rather than physical mask changes, reducing device complexity and enabling rapid design switching.
Solution Approach 2:
The beam splitter system with programmable spatial light modulators serves multiple functions: it can create various beam patterns, switch between different designs, and adapt to different metallic layer configurations, replacing the need for multiple dedicated masks with a single universal system.
3Manufacturing precision
If masks are used in laser impingement demetallization, then design patterns can be transferred to the metallic layer, but production speed decreases due to separate exposure steps and mask handling
Solution Approach 1:
The invention enables continuous demetallization processing by eliminating mask handling steps. The programmable spatial light modulators allow the beam pattern to change electronically between exposures, maintaining continuous production flow without the interruptions required for physical mask changes and removal.
Solution Approach 2:
The invention replaces the mechanical mask system with an optical-electronic control system using programmable spatial light modulators. This substitution eliminates the need for physical mask handling, mounting, and removal, thereby increasing production speed while maintaining pattern transfer accuracy through digital control.
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 rapid and cost-effective production of security elements with complex, angle-dependent designs, enhancing security features by allowing multiple demetallized areas to be created simultaneously, thereby improving production speed and efficiency.
Implementation Method 1
a marking laser source is provided for generating pulsed laser radiation... a plurality of microlenses of the lens grid is simultaneously exposed to the laser beam with the motif-shaped beam cross-section in order to simultaneously produce a plurality of partial motif-shaped demetallized partial areas in the underlying metallic motif layer
Data Source
Figure 1~2
Figure 3~5
Figure 4a~4e
AI summary
The invention relates to a method for manufacturing a security element with a lens raster image (70) for displaying one or more target images (18A, 18B) visible only from predetermined viewing directions, the motifs (22A, 22B) of which are formed by visually recognizable, contrasting metallic sub-areas and demetallized sub-areas (42A, 42B) of a motif layer (40), wherein in the method - a lens raster image (70) with a lens raster consisting of a plurality of microlenses (34) and a metallic motif layer (40) spaced apart from the lens raster is provided, - a marking laser source (52) for generating pulsed laser radiation is provided, - the pulsed laser radiation in the beam path between the laser source (52) and the lens raster image (70) is provided with a motif-shaped beam cross-section by a beam shaper (60) or a switchable mask (82).and - a plurality of microlenses (34) of the lens array are simultaneously acted upon with the laser beam with the motif-shaped beam cross-section (62) in order to simultaneously generate a plurality of partially motif-shaped demetallized sub-areas (42, 42B) in the underlying metallic motif layer (40).