Multipolar Magnet Sensor Geometric Alignment for Position Accuracy
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Solution Overview
Problem
Conventional magnetic sensor devices exhibit low linearity in displacement of magnetic field intensity with movement, leading to reduced position detection accuracy, especially due to positional deviations between the substrate and magnet, affecting resistance value changes and output signals.
Innovation Solution
A magnetic sensor device featuring a multipolar magnet with alternating magnetic poles and a neutral zone, allowing relative movement in a plane parallel to its surfaces, and a magnetic detection part with geometric centers aligned to ensure linear signal changes, utilizing TMR, GMR, or AMR elements for accurate position detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a bipolar magnet with N and S poles is used in conventional magnetic sensor devices, then the device structure is simple, but the linearity of displacement of magnetic field intensity with movement is low, reducing position detection accuracy
Solution Approach 1:
The magnet is divided into multiple poles (multipolar configuration) instead of using a simple bipolar structure. This segmentation creates multiple magnetic field zones that improve the linearity of magnetic field intensity displacement, directly addressing the measurement precision issue while maintaining reasonable structural complexity
Solution Approach 2:
The patent introduces a neutral zone between magnetic poles where the magnetic field intensity is minimized. This local quality change in specific regions (neutral zones) allows for improved overall linearity of magnetic field displacement characteristics, resolving the contradiction between simple structure and high measurement precision
2Device complexity
If GMR elements are arranged at the four corners of a substrate, then the device layout is simple, but positional deviation between substrate center and magnet center causes great changes in resistance values, reducing position detection accuracy
Solution Approach 1:
The patent changes the arrangement parameters of magnetic detection elements from corner positions to positions aligned with the magnet's geometric center. This parameter change in element positioning compensates for assembly deviations and improves position detection accuracy while maintaining a relatively simple device layout
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 enables high-accuracy position detection along one or two axes by ensuring linear changes in sensor signals, minimizing the impact of positional deviations and improving overall detection precision.
Implementation Method 1
a magnetic sensor element, a magnetoresistive effect element (AMR element, GMR element, TMR element or the like) in which resistance changes in accordance with change in the external magnetic field
Implementation Method 2
or a Hall element that utilizes the so-called Hall effect
Data Source
AI summary
A magnetic sensor device has a multipolar magnet having a first surface and a second surface, which is opposite to the first surface, in which magnetic poles of differing polarity are arranged alternately to divide the first surface radially into n regions (where n>4), and a magnetic detection part provided to be opposite to the first surface of the multipolar magnet. The multipolar magnet is provided to be capable of relative movement in at least one direction in a plane substantially parallel to the first surface and the second surface. The magnetic detection part outputs a signal corresponding to change in the magnetic field accompanying relative movement of the multipolar magnet, and the geometric centers of the multipolar magnet and the magnetic detection part substantially match in a direction orthogonal to the first surface.