Triaxial Magnetic Sensor with Crank-Shaped Circuits

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Solution Overview

Problem

Current triaxial magnetic sensors face challenges in reducing size and thickness while maintaining high sensitivity, low noise, and wide measurement range, particularly for applications like smartphones and wearable devices, due to the need for multiple magnetic field detecting elements that increase the device's height and thickness.

Innovation Solution

The use of three magnetic field detecting elements, with two elements positioned point-symmetrically for the x-axial direction and one for the y-axial direction, combined with soft magnetic bodies forming magnetic circuits in a crank shape, allows for reduced size and thickness by optimizing the arrangement and sensitivity of GSR elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If three magnetic sensor elements are assembled to measure magnetic fields in x, y, and z directions, then the measurement capability is improved, but the sensor height increases

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidsensor height
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The patent combines three separate magnetic sensor elements (x-axis, y-axis, and z-axis elements) into a single integrated sensor assembly. The x-axis and y-axis elements are mounted on the substrate surface, while the z-axis element is positioned vertically using a support structure, merging multiple detection functions into one compact unit that maintains low profile height.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from planar arrangement to three-dimensional spatial arrangement by positioning the z-axis magnetic sensor element vertically above the substrate plane using a support structure. This dimensional change allows the z-axis detection capability without increasing the lateral footprint or significantly increasing the overall height.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If multiple magnetic sensor elements are assembled to achieve triaxial detection, then the detection function is improved, but the device complexity increases

Engineering Contradiction:
Improvedetection functionVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs a universal sensor assembly structure that can detect magnetic fields in all three spatial directions (x, y, and z axes) using a standardized configuration. The support structure and substrate arrangement provide a multi-functional platform that integrates three different detection orientations without requiring separate complex assemblies for each axis.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If smartphone thickness is reduced, then the portability is improved, but the azimuth sensor height must be reduced by 40% or more

Engineering Contradiction:
ImproveportabilityVSAvoidazimuth sensor height
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The patent segments the magnetic sensor assembly into distinct functional components: x-axis and y-axis elements mounted on the substrate surface, and a z-axis element positioned vertically with the support structure. This segmentation allows each element to be optimized for its specific detection direction while maintaining a compact overall height suitable for thin smartphones.

Inventive Principle:
Principle #1Segmentation

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 results in a three-dimensional magnetic field detection device with reduced size and thickness, maintaining high sensitivity, low noise, and a wide measurement range, suitable for applications such as smartphones and medical catheters, while also reducing costs.

Implementation Method 1

use is made of Hall elements detecting a magnetic field in the direction perpendicular to a device face, the z-axial element needs to be positioned on the device face while the x-axial and y-axial elements need to be mounted upright on the sensor substrate. In the case of MR elements, MI elements and the like detecting a magnetic field parallel to a device face

Methodology Applied
Scientific EffectGHz spin rotation (GSR) effect:

Implementation Method 2

detects the magnetic field in the z-axial direction by deflecting the magnetic field in the z-axial direction with the permalloy core rod to generate a deflected component in a plane direction

Methodology Applied
Scientific EffectMagnetic field deflection:

Data Source

PatentEP3557271B1Three-dimensional magnetic field detection element and three-dimensional magnetic field detection device
Publication Date: 2022.11.23 ASAHI INTECC CO LTD
  • EP3557271B1 patent drawingFigure 1
  • EP3557271B1 patent drawingFigure 2
  • EP3557271B1 patent drawingFigure 3

AI summary

[Problem] There is a demand for further reductions in the size and thickness of three-dimensional magnetic field detection elements, as well as for improvements in the magnetic field detection capability thereof, in order to expand usefulness into, e.g., a wearable computer having a direction sensor or the distal end of a wire guide of a medical catheter. [Solution] The present invention comprises three soft-magnetic bodies and a magnetic field detection element comprising three GSR elements. For three axial directions that are orthogonal to each other at an origin point that is the center point of measurement, the present invention measures, for a first axial direction, a first-axial-direction magnetic field using two elements sandwiching the origin point, measures, for a second axial direction, a second-axial-direction magnetic field through disposing one element at the position of the origin point, and measures, for a third axial direction, a third-axial-direction magnetic field through combining the two elements for the first axial direction and the three soft-magnetic bodies and forming two crank-shaped magnetic circuits having point symmetry.