Magnetic Flux Absorber With Pinning Portions For Shield Stability

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Solution Overview

Problem

Magnetic shields in magnetic sensors experience unstable magnetization direction due to variations in external magnetic fields, leading to reduced accuracy in detecting magnetic fields, as the magnetization of the shield itself affects the magnetic field detecting element.

Innovation Solution

A magnet flux absorber with a soft magnetic layer and strategically placed magnetically pinning portions that magnetize specific regions differently, creating a multi-domain structure to stabilize the magnetization direction relative to external fields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a soft magnetic layer is forcedly magnetized into a single magnetic domain by a hard bias layer or antiferromagnetic layer, then the magnetization direction is aligned, but the magnetization becomes unstable due to increased magnetostatic energy at edges

Engineering Contradiction:

Improvemagnetization direction stabilityVSAvoidmagnetization stability

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The soft magnetic layer is divided into multiple magnetic domains instead of forcing a single domain structure. The magnetically pinning portions are selectively positioned to create distinct domain regions, allowing the system to reduce magnetostatic energy by forming multiple domains while maintaining controlled magnetization directions through the pinning portions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the soft magnetic layer are given different magnetic properties through selective placement of magnetically pinning portions. The regions facing the pinning portions have their magnetization directions constrained, while other regions form domains naturally to minimize energy, creating local variations in magnetic quality that stabilize the overall structure.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If the magnetization direction of the magnetic shield varies with external magnetic field direction, then the shield adapts to external fields, but the accuracy of magnetic field detection is reduced due to leaking magnetic field variations

Engineering Contradiction:

Improveadaptation to external magnetic fieldVSAvoidmagnetic field detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The magnetic shield is segmented into multiple magnetic domains with different magnetization directions through the selective placement of magnetically pinning portions. This segmentation allows the shield to maintain a more stable overall magnetization pattern that is less sensitive to external field direction changes, thereby improving detection accuracy while retaining some adaptability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention converts the potentially harmful effect of magnetization variation into a beneficial multi-domain structure. By allowing controlled magnetization variations through the pinning portions, the system creates a stable magnetic domain pattern that actually reduces the harmful leaking field variations, turning the adaptation mechanism into a stability-enhancing feature.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

The solution provides a more stable magnetization direction for the magnetic shield, reducing the impact of external magnetic field variations and enhancing the accuracy of magnetic field detection by minimizing magnetostatic energy and maintaining domain stability.

Implementation Method 1

at least one magnetically pinning portion that faces a part of the first surface of the soft magnetic layer or a part of the second surface of the soft magnetic layer. A region of the soft magnetic layer that faces the magnetically pinning portion is magnetized by the magnetically pinning portion in a direction that is different from a direction in which at least a part of remaining region of the soft magnetic layer is magnetized.

Methodology Applied

Scientific EffectMagnetic pinning: Magnetism

Data Source

PatentUS11385302B2Magnetic flux absorber and magnetic sensor having the same

Publication Date: 2022.07.12 TDK CORP

AI summary

A magnet flux absorber of the present invention has a soft magnetic layer having a first surface and a second surface that is a back surface of the first surface, as well as and at least one magnetically pinning portion that faces a part of the first surface of the soft magnetic layer or a part of the second surface of the soft magnetic layer. A region of the soft magnetic layer that faces the magnetically pinning portion is magnetized by the magnetically pinning portion in a direction that is different from a direction in which at least a part of remaining region of the soft magnetic layer is magnetized.