Triangular Magnetoresistive Sensor for Low Offset Angular Detection
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Solution Overview
Problem
Magnetoresistive sensors used for angular detection suffer from high offset and offset drift over temperature, leading to non-reproducible signals, which require sophisticated offset compensation.
Innovation Solution
A magnetoresistive sensor with a triangular structure made of permalloy, featuring three corners with two wiring connections, where the sides have different or substantially equal lengths, allowing for signal conditioning by supplying current to one corner and measuring voltage at the other two, resulting in sinusoidal signals with phase offsets for angular detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional Wheatstone bridge sensors are used for angular detection, then the sensor can detect angular positions, but the offset and offset drift over temperature become high leading to non-reproducible signals
Solution Approach 1:
The patent applies asymmetry by using a triangular sensor element with three different side lengths instead of symmetric configurations. This asymmetric geometry creates inherently different signal paths and resistance values for each corner, which fundamentally changes the signal characteristics and eliminates the offset drift problems associated with traditional symmetric Wheatstone bridge configurations.
Solution Approach 2:
The patent changes the geometric parameters of the sensor element from traditional symmetric shapes to an asymmetric triangle with specific side length ratios. By optimizing the side lengths and corner positions, the patent achieves signal outputs with improved linearity and reduced offset drift over temperature, directly addressing the reliability issue.
2Measurement precision
If three magnetoresistive sensors are arranged as a pyramid, then angular detection is achieved, but the offset compensation becomes complex requiring sophisticated compensation circuits
Solution Approach 1:
The patent merges three magnetoresistive sensing functions into a single triangular sensor element with three corners. This integration allows all three sensing functions to be performed by one compact structure rather than requiring separate sensors and complex compensation circuits, thereby reducing overall device complexity while maintaining angular detection capability.
Solution Approach 2:
The asymmetric triangular geometry inherently provides self-compensation for offset errors through its geometric properties. The different side lengths create naturally balanced signal relationships that eliminate the need for external sophisticated compensation circuits, allowing the sensor to self-correct for temperature drift and offset errors.
3Reliability
If the triangle is made as a hollow structure with inner part left away, then the sensor achieves robust angular detection, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the triangular sensor element into three distinct sides with different lengths, where each side serves a specific sensing function. The hollow structure with removed inner parts creates three separate signal paths that are easier to manufacture individually while maintaining the overall asymmetric geometry needed for robust angular detection.
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 triangular sensor design achieves low offset and robust angular detection with improved linearity and resistance to external disturbances, enabling precise determination of magnetic field angles with reduced need for compensation.
Implementation Method 1
Magnetoresistive sensors are extensively used to detect angular positions or angular movements of elements
Data Source
AI summary
The invention relates to a magnetoresistive sensor with a triangle made of magnetic sensitive material with three corners with two wiring connections, wherein the three sides of the triangle have different or at least substantially equal length.