Magnetic Sensor Field Generators Using Exchange Coupling
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Solution Overview
Problem
Magnetic sensor systems using permanent magnets face challenges in maintaining magnetization direction stability under external disturbance fields and in arranging magnetic field generation units in desired patterns without increasing distance between them, leading to reduced flexibility and resolution.
Innovation Solution
The use of magnetic field generators with ferromagnetic and antiferromagnetic material sections, where the overall magnetization of each unit is defined by exchange coupling, allowing for units with magnetizations in different directions to be arranged closely and maintain immunity to disturbance fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If permanent magnets are used as magnetic field generation units, then the magnetic sensor system can generate stable external magnetic fields, but the magnetization direction may change when exposed to external disturbance fields exceeding the coercivity of the permanent magnets
Solution Approach 1:
The magnetic field generation unit is segmented into multiple ferromagnetic material sections (first, second, third sections) with different magnetization directions. This segmentation allows the unit to generate a composite magnetic field while maintaining stability, as the individual sections are less susceptible to complete magnetization reversal by disturbance fields compared to a single permanent magnet.
Solution Approach 2:
The invention uses composite magnetic field generation units composed of multiple ferromagnetic materials with different magnetic properties and magnetization directions. This composite structure creates a more robust magnetic field source that maintains stability under disturbance fields, combining the advantages of different ferromagnetic materials to resist magnetization changes.
2Measurement precision
If magnetic field generation units are arranged in a predetermined pattern with permanent magnets, then the system can generate alternating external magnetic fields, but the distance between adjacent units cannot be reduced without losing magnetic field strength
Solution Approach 1:
By segmenting each magnetic field generation unit into multiple ferromagnetic sections with alternating magnetization directions, the invention creates stronger localized magnetic fields at smaller dimensions. This allows adjacent units to be placed closer together while maintaining sufficient magnetic field strength for detection, thereby improving spatial resolution.
Solution Approach 2:
The invention changes the magnetic field generation mechanism from relying on strong permanent magnetization to utilizing exchange-coupled ferromagnetic sections with controlled magnetization directions. This parameter change enables more efficient magnetic field generation at smaller scales, allowing reduced spacing between units while maintaining field strength.
3Measurement precision
If magnetic field generation units are arranged closely to improve resolution, then the measurement precision increases, but the magnetic fields from adjacent units may interfere with each other
Solution Approach 1:
The segmentation of magnetic field generation units into sections with alternating magnetization directions creates distinct magnetic field patterns that reduce overlap and interference between adjacent units. This structured arrangement allows closer spacing while maintaining magnetic field independence between neighboring units.
Solution Approach 2:
Each magnetic field generation unit has localized magnetization directions assigned to different sections, creating specific spatial magnetic field distributions. This local quality control ensures that magnetic fields are concentrated where needed while minimizing interference in adjacent regions, enabling closer unit spacing.
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 enables magnetic field generators with high immunity to disturbance fields and allows for flexible and efficient arrangement of magnetic field generation units, improving the resolution and reliability of magnetic sensor systems.
Implementation Method 1
Each of the plurality of magnetic field generation units includes a first ferromagnetic material section and a first antiferromagnetic material section. The first antiferromagnetic material section is in contact with and exchange-coupled to the first ferromagnetic material section. The first ferromagnetic material section has its overall magnetization.
Data Source
AI summary
A magnetic sensor includes a plurality of magnetic detection elements, and a plurality of magnetic field generators associated with the plurality of magnetic detection elements. Each of the plurality of magnetic field generators includes a first ferromagnetic material section and a first antiferromagnetic material section. The first antiferromagnetic material section is in contact with and exchange-coupled to the first ferromagnetic material section. The first ferromagnetic material section has an overall magnetization. The plurality of magnetic field generators includes first and second magnetic field generators configured so that the overall magnetization of the first ferromagnetic material section of the first magnetic field generator is in a different direction from the overall magnetization of the first ferromagnetic material section of the second magnetic field generator.