Inclined-Surface MR Sensor Bias Layer Stacking for Stable Field Detection

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Solution Overview

Problem

Magnetic sensors with magnetoresistive elements disposed on inclined surfaces experience variations in applied magnetic fields due to manufacturing inaccuracies, particularly when multiple-layer magnetic field generators are used, leading to inconsistent bias magnetic fields.

Innovation Solution

A magnetic sensor design with ferromagnetic and antiferromagnetic material sections stacked intersecting an inclined surface, ensuring consistent magnetic field application to magnetoresistive elements, reducing variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If magnetoresistive elements are disposed on an inclined surface to detect perpendicular magnetic field components, then the sensor can detect magnetic fields in a direction perpendicular to the substrate surface, but the bias magnetic field strength or direction varies due to manufacturing variations in element or generator positions

Engineering Contradiction:

Improvemagnetic field detection capabilityVSAvoidpositional accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies dimensionality change by stacking the ferromagnetic and antiferromagnetic material sections in a direction intersecting the inclined surface (vertical stacking), rather than arranging them side-by-side along the inclined surface. This vertical stacking configuration ensures that the bias magnetic field application points are positioned above and below the magnetoresistive element in the vertical dimension, making the magnetic field application less sensitive to horizontal positional variations caused by manufacturing tolerances.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If magnetic field generators with multiple layers are used to apply bias magnetic fields, then the magnetic field application can be more precise, but variations in magnetic field strength or direction occur due to manufacturing variations

Engineering Contradiction:

Improvemagnetic field application precisionVSAvoidmagnetic field consistency

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent uses composite materials by combining ferromagnetic and antiferromagnetic material sections in a stacked configuration. The ferromagnetic layer generates the bias magnetic field while the antiferromagnetic layer provides exchange coupling to stabilize the magnetization direction. This composite structure enhances both the precision and reliability of magnetic field application by leveraging the complementary properties of different materials.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The stacked configuration of ferromagnetic and antiferromagnetic layers in the direction intersecting the inclined surface creates a vertical arrangement that reduces sensitivity to horizontal manufacturing variations. This dimensional arrangement ensures consistent magnetic field application despite positional deviations in the magnetoresistive elements or magnetic field generators.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Measurement precision

If bias magnetic field application units with sandwiched magnetic layer structures are used, then offset reduction is achieved, but the device complexity increases

Engineering Contradiction:

Improveoffset reductionVSAvoidstructure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the bias magnetic field generation function with the magnetic field application structure by integrating ferromagnetic and antiferromagnetic material sections into a unified stacked configuration. This merging approach achieves offset reduction through the composite material structure while avoiding the need for separate, complex bias field application units, thereby reducing overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 design stabilizes the magnetic field applied to magnetoresistive elements, enhancing the accuracy and reliability of magnetic field detection.

Implementation Method 1

an antiferromagnetic material section that is in contact with the ferromagnetic material section and is in exchange coupling with the ferromagnetic material section

Methodology Applied

Scientific EffectExchange coupling:

Data Source

PatentUS12618921B2Magnetic sensor including magnetic detection element and magnetic field generator disposed on inclined surface

Publication Date: 2026.05.05 TDK CORP

AI summary

A magnetic sensor includes an insulating layer having a first inclined surface, a plurality of first MR elements disposed on the first inclined surface, and a plurality of first magnetic field generators disposed on the first inclined surface and configured to generate a magnetic field to be applied to the plurality of first MR elements. Each of the plurality of first magnetic field generators includes a ferromagnetic material section and an antiferromagnetic material section. The ferromagnetic material section and the antiferromagnetic material section are stacked in a direction intersecting the first inclined surface.