Planar Magnetoimpedance Sensor Element with Embedded Amorphous Wire

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional magneto-impedance (MI) sensor elements with amorphous wires face challenges in reducing size and thickness while maintaining output characteristics, and are limited by the need for stress-free wire arrangement and substrate materials, which complicates microfabrication and increases costs due to the use of machinable ceramics.

Innovation Solution

A magneto-impedance sensor element with a substrate of non-magnetic material, featuring a planar pattern of conductive films, an amorphous wire aligned with the pattern, and a three-dimensional pattern formed over an insulator that increases in width towards the planar pattern, allowing for a stress-free wire arrangement and reduced substrate thickness without the need for an extending groove.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If an amorphous wire is shortened and detecting coil is wound only around the wire without outer peripheral winding of substrate, then size reduction is achieved, but stress-free arrangement of amorphous wire on detecting coil pattern becomes difficult

Engineering Contradiction:
Improvesize of MI elementVSAvoidmagnetic characteristics stability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent transitions from a conventional three-dimensional winding structure to a planar two-dimensional pattern structure. The detecting coil is formed as a planar pattern on the substrate surface, and the amorphous wire is arranged directly on this planar pattern, eliminating the need for outer peripheral winding of the substrate. This dimensional change enables size reduction while maintaining stress-free wire arrangement.

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

Solution Approach 2:

The invention extracts and eliminates the extending groove structure from the substrate. By removing this recessed portion, the patent simplifies the overall structure, enables thinner substrates, and eliminates the complexity of burying the amorphous wire in a groove, thereby achieving size reduction without compromising reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If an extending groove is formed in substrate to bury amorphous wire, then stress-free arrangement is achieved, but substrate may be damaged and microfabrication complexity increases

Engineering Contradiction:
Improvestress-free wire arrangementVSAvoidmicrofabrication process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the extending groove structure from the substrate design. By eliminating this recessed portion, the invention simplifies the microfabrication process, reduces the risk of substrate damage during groove formation, and decreases overall device complexity while maintaining stress-free wire arrangement through the planar pattern approach.

Inventive Principle:
Principle #2Taking out (Extraction)

3Volume of moving object

If substrate thickness is reduced, then size reduction is achieved, but substrate strength decreases and breakage risk increases

Engineering Contradiction:
Improvethickness of MI elementVSAvoidsubstrate strength
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

By transitioning to a planar pattern structure, the patent eliminates the need for a thick substrate to provide mechanical support for groove formation and wire burial. The simplified structure allows for thinner substrates without compromising overall device strength, as the planar coil pattern and surface-mounted wire arrangement do not require the structural reinforcement that groove-based designs demand.

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

4Measurement precision

If conventional MI element structure is used, then high sensitivity is achieved, but size reduction is limited

Engineering Contradiction:
Improvesensitivity of magnetic sensorVSAvoidsize of MI element
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent achieves size reduction while maintaining sensitivity by transitioning to a planar pattern structure. The detecting coil is formed as a two-dimensional pattern on the substrate surface, allowing for compact integration and reduced overall dimensions. The amorphous wire is arranged directly on the planar pattern, enabling close proximity between the wire and coil turns, which maintains the magnetic coupling necessary for high sensitivity detection.

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

Solution Approach 2:

The invention employs thin-film technology for forming the detecting coil pattern on the substrate surface. This approach allows for compact, planar integration of the coil structure, enabling size reduction while maintaining the electrical and magnetic properties necessary for sensitive detection. The thin-film approach is compatible with standard microfabrication processes.

Inventive Principle:
Principle #30Flexible shells and thin films

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 sensor's sensitivity, reduces size and thickness, and increases the freedom in choosing substrate materials, preventing substrate breakage and improving microfabrication processability, while maintaining or exceeding the output characteristics of conventional MI elements.

Implementation Method 1

an amorphous wire serving as a magnetic core of an MI element is crystallized in solder connection by heating

Methodology Applied
Scientific EffectMagnetoimpedance effect: Magnetoresistance

Data Source

PatentEP2402778B1Magnetoimpedance sensor element and method for manufacturing the same
Publication Date: 2014.04.16 AICHI STEEL CORP
  • EP2402778B1 patent drawingFigure 1~2
  • EP2402778B1 patent drawingFigure 3
  • EP2402778B1 patent drawingFigure 4(a)~4(b)

AI summary

A magneto-impedance sensor element is formed in a planar type structure in which an amorphous wire is incorporated in a substrate. The magneto-impedance sensor element includes a nonmagnetic substrate, an amorphous wire arranged in an aligning direction of a planar pattern that forms a detecting coil, a spiral detecting coil formed of a planar pattern and a cubic pattern on an outer periphery of the amorphous wire, a planar insulating portion that insulates the planar pattern from the amorphous wire, a wire fixing portion to fix the amorphous wire on an upper surface of the planar insulating portion, and a cubic insulating portion that insulates the cubic pattern from the amorphous wire.