Magnetic Sensor Magnetoresistive Element Bias Field Stabilization
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Solution Overview
Problem
Current magnetic sensors face challenges in producing highly accurate and stable sensor signals due to instability in magnetization, particularly in magnetoresistive effect elements like AMR, GMR, and TMR elements, which affects their performance in applications such as position detection and current measurement in hybrid and electric vehicles.
Innovation Solution
A magnetic sensor design incorporating a magnetoresistive effect element with a bias magnetic field generation unit and yoke units to stabilize magnetization, featuring a specific configuration of yoke units and bias magnetic field generation units that focus external magnetic fields and apply a bias field to improve sensitivity and reduce hysteresis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnet is added to apply bias magnetic field on the ferromagnetic layer or free layer, then the accuracy of sensor signal is improved, but the device complexity increases
Solution Approach 1:
The bias magnetic field generation unit is integrated with the yoke units to form a unified magnetic field management structure. This merging reduces the number of separate components and simplifies the overall device architecture while maintaining the necessary bias field application capability for accurate sensor signals
Solution Approach 2:
The yoke units serve dual purposes: they both guide the external magnetic field to the magnetoresistive effect element and work in conjunction with the bias magnetic field generation unit to stabilize magnetization. This multi-functionality reduces the need for separate dedicated components, thereby reducing device complexity
2Measurement precision
If yoke units are added to focus external magnetic fields, then sensitivity is improved, but device complexity increases
Solution Approach 1:
The bias magnetic field generation unit is integrated with the yoke units to form a unified magnetic field management structure. This merging reduces the number of separate components and simplifies the overall device architecture while maintaining the necessary bias field application capability for accurate sensor signals
Solution Approach 2:
The yoke units serve dual purposes: they both guide the external magnetic field to the magnetoresistive effect element and work in conjunction with the bias magnetic field generation unit to stabilize magnetization. This multi-functionality reduces the need for separate dedicated components, thereby reducing device complexity
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 enhances the sensitivity and stability of sensor signals, enabling more accurate position detection and current measurement, while controlling hysteresis and improving the overall performance of magnetic sensors.
Implementation Method 1
a magnetoresistive effect element (an AMR element, GMR element, TMR element or the like), the resistance of which changes in accordance with change in the external magnetic field or the like is known
Implementation Method 2
a first bias magnetic field generation unit provided adjacent to the first end surface of the magnetoresistive effect element, wherein the first bias magnetic field generation unit is provided so as to be capable of applying a bias magnetic field on the magnetoresistive effect element and the first yoke unit
Implementation Method 3
a first yoke unit provided adjacent to the first side surface of the magnetoresistive effect element
Data Source
AI summary
A magnetic sensor comprises a magnetoresistive effect element including a first side surface and a second side surface facing in opposite directions along a first axis and a first end surface and a second end surface facing in opposite directions along a second axis substantially orthogonal to the first axis. The sensor has a sensitivity axis extending in a direction of the first axis, a first yoke unit provided adjacent to the first side surface of the magnetoresistive effect element, and a first bias magnetic field generation unit provided adjacent to the first end surface of the magnetoresistive effect element. The first bias magnetic field generation unit is provided to be capable of applying a bias magnetic field on the magnetoresistive effect element and the first yoke unit.