Domain Wall Sensor Element for Non-Volatile Position Storage

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Solution Overview

Problem

Existing position measuring devices, such as angle and length measuring devices, face challenges in storing rotation or position information in a non-volatile manner without requiring auxiliary electrical energy, especially in applications where power may be unavailable.

Innovation Solution

A sensor element with a domain wall conductor on a substrate, featuring a course without crossings and an electrically conductive layer for generating magnetic fields to create and move domain walls, allowing for active storage of information without auxiliary energy by utilizing a support magnet and readout elements like GMR or TMR sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If domain wall conductors with intersections are used for storing position information, then the storage capacity is increased, but the initialization and reset processes become more complex and costly

Engineering Contradiction:
Improvestorage capacityVSAvoidinitialization complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent removes the problematic intersection points from the domain wall conductor path, creating a simplified continuous path that eliminates the need for complex initialization procedures while maintaining adequate storage capacity through the use of domain walls along the streamlined path

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If auxiliary electrical energy is used for storing position information, then the reliability of data storage is improved, but the device requires continuous power supply which reduces its applicability in power-free scenarios

Engineering Contradiction:
Improvedata storage reliabilityVSAvoidauxiliary energy requirement
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The sensor element utilizes the magnetic field generated by the current-carrying conductor itself to create and position domain walls, eliminating the need for auxiliary electrical energy or external initialization systems. The domain walls store position information passively without requiring continuous power supply

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If the electrically conductive layer is positioned parallel to the substrate, then the manufacturing process is simplified, but the magnetic field generation efficiency for creating domain walls is reduced

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmagnetic field generation efficiency
Core Design Contradiction:
Ease of manufactureVSPower

Solution Approach 1:

The electrically conductive layer is positioned in a third dimension (vertical/axial direction) above the substrate plane, creating a three-dimensional layered structure. This spatial arrangement optimizes the magnetic field generation efficiency for domain wall creation while maintaining manufacturability through standard layer deposition techniques

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

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

Enables reliable storage and retrieval of position information, including the number of revolutions, in angle measuring devices and linear scales, ensuring data integrity even during power failures, with the ability to count both directions of rotation.

Implementation Method 1

applying an electrical voltage to two contact points causes an electric current to flow in a first current direction, so that domain walls can be generated in the domain wall conductor by its magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the sensor element can be initialized or reset by a magnetic field of a support magnet superimposed on the generated magnetic field

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 3

readout elements like GMR or TMR sensors

Methodology Applied
Scientific EffectGiant magnetoresistance (GMR): Magnetoresistance

Data Source

PatentEP4266007B1Sensor element for storing rotation or position information and storage system comprising a sensor element
Publication Date: 2024.12.18 DR JOHANNES HEIDENHAIN GMBH
  • EP4266007B1 patent drawingFigure 1a~1b
  • EP4266007B1 patent drawingFigure 2~4
  • EP4266007B1 patent drawingFigure 5~6

AI summary

The invention relates to a sensor element (1; 1') comprising a domain wall conductor (1.1; 1.1') arranged on a substrate (1.2), wherein the domain wall conductor (1.1; 1.1') is designed to be free of intersections and has a first region (A) with a positive curvature and a second region (B) with a negative curvature. Furthermore, the sensor element (1; 1') comprises an electrically conductive layer (1.7) applied to the substrate (1.2) which is arranged overlapping with and electrically insulated from the domain wall conductor (1.1; 1.1'). The electrically conductive layer (1.7) has four contact points (1.71, 1.72, 1.73, 1.74) arranged such that two pairs of contact points (1.71, 1.72, 1.73, 1.74) an electrical voltage can be applied so that an electric current flows either in the first current direction (ξ) or in a second current direction (ψ), wherein the first current direction (ξ) is oriented orthogonally to the second current direction (ψ), so that domain walls (W1, W2, W1', W2') can be generated by the magnetic field induced in the domain wall conductor (1.1; 1.1').