Magnetic Sensor Radial Annular Elements Disturbance Field Discrimination
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Solution Overview
Problem
Magnetic sensors using MR sensors face difficulties in distinguishing between the angle of a magnetic vector of a magnet and a disturbance magnetic field, leading to erroneous determinations when a disturbance magnetic field is present.
Innovation Solution
A magnetic sensor design comprising radial and annular or polygonal magnetoresistance elements arranged in specific configurations, with half-bridge circuits formed by these elements, allowing for discrimination between the magnetic field of a detection target and a disturbance field based on differing magnetoresistance value changes with respect to the magnetic field direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a disturbance magnetic field is applied, then the magnetic sensor can detect a magnetic field, but it cannot discriminate whether the detected angle is from the magnet or the disturbance magnetic field, causing erroneous determination
Solution Approach 1:
The magnetoresistance elements are segmented into two distinct groups with different orientations: radial elements (detecting both radial and tangential magnetic field components) and annular elements (detecting only tangential magnetic field components). This segmentation allows the system to differentiate between the magnetic field from the magnet and disturbance magnetic fields by comparing the detection patterns of the two groups.
Solution Approach 2:
Different magnetoresistance elements are given different local qualities through their orientation configurations. The radial magnetoresistance elements have a different detection characteristic compared to the annular magnetoresistance elements, allowing them to respond differently to the same magnetic field conditions and enabling discrimination between signal and noise.
2Reliability
If radial and annular magnetoresistance elements are used with different orientations, then discrimination between target and disturbance magnetic fields is enabled, but device complexity increases
Solution Approach 1:
The radial and annular magnetoresistance elements are merged into a single integrated sensor structure that functions as one cohesive unit. Both types of elements share common connection nodes and are processed together in the determination logic, reducing overall system complexity despite the different orientations of individual elements.
Solution Approach 2:
The magnetoresistance elements serve multiple functions: they detect magnetic field direction, provide redundancy for error correction, and enable discrimination between target and disturbance fields. This multi-functionality reduces the need for separate components and simplifies the overall device architecture.
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 sensor effectively differentiates between the target and disturbance magnetic fields, preventing erroneous determinations and ensuring accurate operation even in environments with disturbance fields.
Implementation Method 1
a magnetic sensor comprises a radial magnetoresistance element comprising a plurality of magnetic sensing parts arranged radially from one point, an annular or polygonal magnetoresistance element arranged so as to surround the radial magnetoresistance elements
Data Source
AI summary
A magnetic sensor includes a radial magnetoresistance element including plural magnetic sensing parts arranged radially from one point, an annular or polygonal magnetoresistance element arranged so as to surround the radial magnetoresistance elements, and at least one half-bridge circuit including the radial magnetoresistance element and the annular or polygonal magnetoresistance element. The radial magnetoresistance element may include a first magnetoresistance element including plural first magnetic sensing parts and a second magnetoresistance element including plural second magnetic sensing parts. The annular or polygonal magnetoresistance element may include an annular or polygonal third magnetoresistance element surrounding the first and second magnetoresistance elements and an annular or polygonal fourth magnetoresistance element surrounding the third magnetoresistance element. Two half-bridge circuits including the first to fourth magnetoresistance elements may be installed in the magnetic sensor.