Card Reader Interfering Magnetic Field Mechanism
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Solution Overview
Problem
Existing card readers have difficulty expanding the influence range of their interfering magnetic fields to prevent unauthorized reading by skimming magnetic heads, especially when these heads are positioned distant from the card insertion slot.
Innovation Solution
The card reader design includes a configuration of independent soft magnetic core parts with distinct orientations and separate drive circuits for each coil, allowing for a complex interfering magnetic field generation mechanism that reduces magnetic flux leakage and increases the field's influence range by suppressing unwanted magnetic paths and enhancing field intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the core parts are interconnected to form a magnetic path, then the magnetic field generation is enhanced, but the influence range of the interfering magnetic field is limited
Solution Approach 1:
The core is divided into multiple independent core parts (first core part, second core part, third core part) that are not interconnected. Each core part has its own coil and can generate magnetic flux independently. This segmentation prevents the formation of closed magnetic paths between core parts, forcing magnetic flux to extend outward into the space around the card movement path, thereby expanding the influence range of the interfering magnetic field while maintaining field generation capability.
2Reliability
If separate drive circuits are used for different coils, then a complex interfering magnetic field is generated, but the device complexity increases
Solution Approach 1:
Multiple coils (first coil, second coil, third coil) are connected in series to form a single coil assembly that is driven by one drive circuit. The series connection allows different sections of the coil assembly to generate magnetic flux in different directions and characteristics, creating a complex interfering magnetic field pattern. This merging approach achieves the same skimming prevention capability as separate drive circuits but with reduced device complexity and fewer components.
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 configuration effectively expands the interfering magnetic field's range, preventing unauthorized data reading from a greater distance, while maintaining the complexity of the generated field to protect magnetic data on cards.
Implementation Method 1
a first coil that is a coil wound around the first core part... When alternating current is supplied to the first coil and the second coil, an AC magnetic field is generated
Data Source
AI summary
In a card reader, an interfering magnetic field generation mechanism 11 includes a core part 14a, a core part 14b, and a core part 15a, each of which is formed of soft magnetic material in a straight line, a coil 16 that is wound around the core part 14a, a coil 17 that is connected to the coil 16 in series and is wound around the core part 14b, a coil 18 that is wound around the core part 15a, a first drive circuit that supplies alternating current to the coils 16 and 17, and a second drive circuit that supplies alternating current to the coil 18. The core part 15a is disposed between the core part 14a and the core part 14b. The core part 15a is formed independently of the core parts 14a and 14b, and is separated from the core parts 14a and 14b.