Atomic Magnetic Field Imaging via Phase Image Segmentation

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Solution Overview

Problem

Existing methods, such as electron beam holography and differential phase-contrast imaging, face challenges in distinguishing between electric and magnetic fields at the atomic level due to strong electric fields from atomic nuclei, making it difficult to observe weaker magnetic fields generated by electron spins.

Innovation Solution

An image processing method that acquires phase images of electromagnetic fields in columns of atoms, analyzes the period of electric fields, and separates electromagnetic fields into magnetic and electric components by comparing fields in adjacent columns, allowing for the extraction of magnetic field distributions at atomic resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electron beam holography or DPC method is used to image phase variations, then phase variations can be visualized, but it becomes difficult to discern whether the phase variations are caused by electric fields or magnetic fields

Engineering Contradiction:
Improvephase variation detection capabilityVSAvoidfield type discrimination difficulty
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the electromagnetic field measurement problem by acquiring phase images from multiple different incident directions (at least two directions). By dividing the measurement into multiple directional components, the method enables separate determination of electric and magnetic field distributions through mathematical processing of the combined phase information.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary computational process that uses the phase images obtained from different incident directions as intermediate data. Through mathematical processing involving the relationship between phase shifts and field components, this intermediary computation separates the mixed electric and magnetic field effects into distinct measurable quantities.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If high resolution imaging is performed to observe atomic level structures, then atomic nuclei and their electric fields are clearly resolved, but the weaker magnetic fields from electron spins become even more difficult to distinguish

Engineering Contradiction:
Improvespatial resolutionVSAvoidmagnetic field signal detection
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent segments the field measurement by obtaining phase images from multiple incident directions. This segmentation allows the subsequent mathematical processing to separate the dominant electric field contributions (which vary systematically with incident direction) from the weaker magnetic field signals (which have different directional dependencies), thereby recovering magnetic field information that would be lost in single-direction imaging.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent converts the harmful effect of dominant electric fields that mask magnetic fields into a beneficial separation process. By measuring phase variations from multiple incident directions, the method exploits the different transformation behaviors of electric and magnetic fields under direction changes to isolate the magnetic field signal from the overwhelming electric field background.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Difficulty of detecting and measuring

If sample inversion is used to separate electric and magnetic fields by reversing beam direction, then field separation becomes possible, but it becomes difficult to measure exactly the same portion of sample at atomic level before and after inversion

Engineering Contradiction:
Improvefield separation capabilityVSAvoidmeasurement position alignment
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent applies the inversion principle by acquiring phase images with electron beams incident from different directions (effectively inverting the measurement geometry). However, instead of physically inverting the sample, the method achieves field separation through computational processing of images taken with the sample in its original position but illuminated from multiple directions, thereby avoiding the positioning alignment problem.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces the mechanical sample inversion system with a computational approach. Instead of physically flipping the sample and attempting to re-align it to the same atomic positions, the method uses mathematical processing on phase images acquired from different incident directions to achieve field separation, substituting mechanical operations with information processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 the generation of high-resolution images representing magnetic field distributions at the atomic level, overcoming the challenge of distinguishing magnetic fields from dominant electric fields.

Implementation Method 1

When an electron beam impinges on a sample, the beam may undergo phase variations from the sample

Methodology Applied
Scientific EffectPhase variation of electron beam: Lorentz Force

Implementation Method 2

the direction of the electric field induced force included in the Lorentz forces that the electron beam undergoes from the electromagnetic field

Methodology Applied
Scientific EffectElectromagnetic field interaction: Lorentz Force

Data Source

PatentEP3943923B1Method and apparatus for image processing
Publication Date: 2023.04.19 JEOL LTD
  • EP3943923B1 patent drawingFigure 1~3
  • EP3943923B1 patent drawingFigure 4~6
  • EP3943923B1 patent drawingFigure 7~8

AI summary

There is provided an image processing method capable of generating an image representative of a magnetic field distribution. The method starts with acquiring phase images providing visualization of electromagnetic fields respectively in a plurality of columns (S10). Then, each of the electromagnetic fields in the columns within the phase images is separated into magnetic field and electric field components (S30). An image representative of a magnetic field distribution is created based on the separated magnetic field components (S40). The step of separating each electromagnetic field includes separating the electromagnetic field in a first one of the columns into magnetic field and electric field components based on the electromagnetic field in a second one of the columns, the latter electromagnetic field having an electric field component oriented in the same direction as that in the first column.