Optically Variable Magnetic Stripe With Segmented Metallic Reflecting Layer
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Solution Overview
Problem
Conductive metallic reflection enhancing layers in Optically Variable Magnetic (OVM) stripes on financial transaction cards cause electrostatic discharge (ESD) issues in Automatic Teller Machines (ATMs) and point of sale (POS) systems, leading to potential system failures and interference.
Innovation Solution
The OVM stripe assembly features a metallic reflecting layer with an array of spaced metallic regions shaped as regular polygons, separated by insulating materials to control electrostatic breakdown and minimize ESD, while maintaining the brightness and clarity of the hologram image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a continuous metallic reflection enhancing layer is used in the OVM stripe, then the brightness and clarity of the hologram image is improved, but electrostatic discharge (ESD) issues occur in ATM and POS systems
Solution Approach 1:
The continuous metallic reflection enhancing layer is divided into an array of spaced metallic regions (cells) separated by insulating material. This segmentation reduces the conductive path length and prevents electrostatic discharge while maintaining sufficient metallic area to preserve hologram brightness and clarity.
Solution Approach 2:
The metallic regions are shaped as regular polygons with specific geometric properties (minimum internal angles of 90 degrees, preferably 108 degrees for hexagons) to optimize both optical performance and electrostatic breakdown control. The local geometry of each cell is designed to balance light reflection needs with ESD prevention requirements.
2Object-affected harmful factors
If the spacing between metallic regions is increased to prevent electrostatic breakdown, then ESD protection is improved, but the brightness of the hologram image decreases
Solution Approach 1:
The spacing between metallic regions is optimized to a specific range (0.02-0.15 mm, preferably 0.04-0.08 mm) that provides sufficient electrostatic breakdown protection (up to 25 kV) while maintaining adequate metallic area density to preserve hologram brightness. This parameter optimization resolves the trade-off between ESD protection and optical performance.
Solution Approach 2:
The metallic reflecting layer is combined with insulating material to form a composite structure. This composite design allows the metallic regions to provide both optical reflection and electrostatic protection, while the insulating material fills the spaces to prevent discharge paths without significantly blocking light.
3Object-affected harmful factors
If regular polygon shapes with minimum internal angles of 90 degrees are used for metallic regions, then control over electrostatic breakdown is improved, but manufacturing precision requirements increase
Solution Approach 1:
The requirements for electrostatic breakdown control and manufacturing feasibility are merged by selecting regular polygon shapes (particularly hexagons) that satisfy both criteria. The 108-degree internal angle of hexagons provides optimal electrostatic field distribution while being readily manufacturable using standard screen printing and electroforming 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
This design effectively prevents electrostatic discharge by controlling the spacing between metallic regions to prevent electrostatic breakdown up to 25 kV, reducing the risk of system interference and maintaining the visual integrity of the hologram, thus ensuring the stability and functionality of electronic card readers.
Implementation Method 1
a metallic reflecting layer adjacent the optically variable effect generating layer
Implementation Method 2
comprising an array of spaced metallic regions shaped as regular polygons... effectively prevents electrostatic discharge by controlling the spacing between metallic regions to prevent electrostatic breakdown up to 25 kV
Data Source
AI summary
An optically variable magnetic stripe assembly comprises a magnetic layer (5); an optically variable effect generating layer (1) over the magnetic layer; and a metallic reflecting layer (3) adjacent the optically variable effect generating layer and comprising an array of spaced metallic regions shaped as regular polygons.