Perforated Plastic Watermark Insert for High-Contrast Paper Security
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for producing two-stage watermarks in paper are limited by structural requirements and stability issues, restricting design freedom and visual appeal, especially in security papers like banknotes.
Innovation Solution
A drainage wire with a perforated plastic watermark insert featuring opposing motif components with distinct characteristic dimensions and sharp edges, integrated into a carrier screen, allowing for high-security, visually appealing, and complex designs through injection molding or deep-drawing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal wires or shaped metal parts (electrotypes) are soldered onto the screen structure to produce two-stage watermarks, then the watermark stability is improved, but the design freedom and visual appeal are restricted
Solution Approach 1:
The patent changes the material parameter from metal to plastic and the manufacturing method from soldering to injection molding. This allows the watermark insert to be produced as a single piece with complex geometries, elevations, and depressions that would be difficult or impossible to achieve with traditional metal electrotypes, thereby increasing design freedom while maintaining stability
Solution Approach 2:
The patent uses a composite structure combining a mesh-like carrier fabric with a solid plastic watermark insert. This composite approach allows the flexible carrier to conform to the drum surface while the rigid plastic insert provides stable, precise watermark features with complex designs, resolving the contradiction between stability and design freedom
2Reliability
If the characteristic dimension of watermark motif structures is reduced to increase security against forgery, then the security level is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent replaces traditional mechanical watermark production methods (soldering metal wires, hand-crafting electrotypes) with injection molding technology. This manufacturing substitution enables precise reproduction of complex, small-scale features with sharp edges at scale, reducing manufacturing complexity while enhancing security through intricate, difficult-to-reproduce designs
Solution Approach 2:
The injection molding process allows precise control of dimensional parameters, enabling the production of watermark features with characteristic dimensions reduced by factors of 3 or more while maintaining sharp edges and high precision. This parameter control reduces manufacturing complexity compared to traditional methods while increasing security
3Shape
If multi-level watermarks with smooth transitions are used to improve visual appeal, then the aesthetic quality is improved, but the security against forgery is reduced compared to two-stage watermarks
Solution Approach 1:
The patent applies local quality by creating distinct regions within the watermark insert: some areas with elevations for light motif structures, others with depressions for dark motif structures, and transition areas with specific height profiles. This local differentiation enables sharp two-stage transitions in critical security areas while allowing smoother transitions in aesthetic areas, combining both requirements
Data Source
Figure 1~2
Figure 3~4
Figure 5a~5d
AI summary
The invention relates to a dewatering screen (40) for the production of paper with a two-stage watermark (14, 16), and in which, according to the invention, it is provided that the motif depicted by the watermark (14, 16) contains at least two contrasting motif components (20, 30; 80, 90), that the dewatering screen (40) has a carrier screen (42) and a perforated plastic watermark insert (54) arranged in a partial area of the carrier screen (42), and that the plastic watermark insert (54) has a base body (56) with at least two contrasting motif generation areas (60, 70; 110, 120) with motif elements (62, 72;112, 122) for generating the motif components of the watermark motif, wherein K1): at least one motif generation area (60) has, as motif elements (62), elevations projecting from the base body (56) and at least one motif generation area (70) has, as motif elements (72), depressions projecting into the base body (56), or K2): at least one motif generation area (110) has motif elements (112) with a small characteristic lateral dimension (114) and at least one motif generation area (120) has motif elements (122) with a large characteristic lateral dimension (124), wherein the large characteristic lateral dimension (124) is at least 3 times larger than the small characteristic lateral dimension (122).;