Magnetic Sensor with Semicircular Bridge Circuits for Position Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing magnetic sensors used in position detectors have limitations in detection accuracy due to the arrangement of magnetoresistive elements, which affects the strength of the magnetic field applied and the precision of position detection.

Innovation Solution

The magnetic sensor employs a first and second bridge circuit with serpentine magnetoresistive elements arranged in a semicircular pattern, outputting detection signals with a sine-cosine relationship, allowing for improved position detection accuracy by ensuring a strong magnetic field is applied and reducing field differences between sensor elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetoresistive elements are arranged in a conventional configuration, then the device complexity is reduced, but the detection accuracy deteriorates due to insufficient magnetic field strength and field differences between sensor elements

Engineering Contradiction:

Improvedetection accuracyVSAvoidsensor element arrangement complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor elements are arranged in a semicircular pattern rather than a linear or rectangular configuration. This curved arrangement allows all sensor elements to be equidistant from the center of rotation, ensuring uniform magnetic field exposure and reducing field differences between elements, thereby improving detection accuracy

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The sensor elements are divided into two bridge circuits (first and second bridge circuits) with each circuit containing multiple magnetoresistive elements. This segmentation allows for differential measurement and signal processing that enhances detection accuracy while managing the complexity through structured organization

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If sensor elements are arranged to detect position with high precision, then the detection accuracy is improved, but the magnetic field strength applied to the sensor elements becomes insufficient

Engineering Contradiction:

Improveposition detection precisionVSAvoidmagnetic field strength

Core Design Contradiction:

Measurement precisionVSForce

Solution Approach 1:

The semicircular arrangement positions all sensor elements at equal radial distances from the center of rotation, ensuring that the magnetic field strength is uniform across all elements. This geometric configuration maximizes the magnetic field exposure for position detection without requiring additional field strength

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

Each magnetoresistive element in the bridge circuits is configured with specific resistance characteristics and is positioned at a specific angular location in the semicircle. This local optimization ensures that each element operates in its optimal range while collectively providing high-resolution position detection

Inventive Principle:

Principle #3Local quality

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

This configuration enhances the detection accuracy of the position detector by ensuring a strong magnetic field is applied and reducing field differences, thereby improving the precision of position detection.

Implementation Method 1

the resistance changes in accordance with the magnetic field applied to the magnetoresistive elements

Methodology Applied

Scientific EffectMagnetoresistive effect: Magnetoresistance

Data Source

PatentUS11422007B2Magnetic sensor including sensor elements of bridge circuits arranged along a partial circle circumference about a center of the sensor elements

Publication Date: 2022.08.23 KK TOKAI RIKA DENKI SEISAKUSHO

AI summary

A magnetic sensor includes first and second bridge circuits. The first bridge circuit includes a first group of magnetoresistive elements connected in a bridge. The first bridge circuit outputs a first detection signal corresponding to a magnetic field detected by the magnetoresistive elements in the first group. The second bridge circuit includes a second group of magnetoresistive elements connected in a bridge. Each magnetoresistive element of the first and second bridge circuits is formed by a sensor element bent in a serpentine manner. The second bridge circuit outputs a second detection signal corresponding to a magnetic field detected by the magnetoresistive elements in the second group and having a waveform that has a sine-cosine relationship with the first detection signal. The sensor elements of the first and second bridge circuits are arranged along a circumference of part of a circle about a center of the sensor elements.