Electron Microscope Hollow-Cone Illumination for Magnetic Observation
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Solution Overview
Problem
Current methods for observing magnetic material magnetization distribution and dielectric material polarization structure using transmission electron microscopes suffer from low spatial resolution, orientation dependency, and inability to observe electromagnetic fields due to limitations in the Lorenz microscopy techniques such as the Fresnel and Foucault methods.
Innovation Solution
An electron microscope system with two-stage electron beam deflectors that orbits the electron beam around the optical axis, allowing for in-focus, high-resolution imaging of weak scatterers and phase objects by adjusting the irradiation angle within a predetermined range, and using a hollow-cone illumination method to achieve high-resolution imaging without orientation dependency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If defocusing is performed to visualize domain boundary (Fresnel method), then electromagnetic structure can be observed, but spatial resolution deteriorates
Solution Approach 1:
The patent applies dynamic illumination by rotating the electron beam around the optical axis to sweep through all azimuth angles. This dynamic approach replaces the static defocusing method, allowing the system to collect diffraction information from all orientations without sacrificing spatial resolution. The beam rotation enables in-focus imaging while maintaining electromagnetic structure observation capability.
Solution Approach 2:
The patent introduces a temporal dimension to the observation process by rotating the beam over time. Instead of using spatial defocusing (Fresnel method), the system uses temporal integration of diffraction patterns acquired at different azimuth angles. This dimensional transformation allows simultaneous achievement of high spatial resolution and electromagnetic structure visualization.
2Measurement precision
If aperture hole position is used to shield electron beam (Foucault method), then electromagnetic structure contrast can be obtained, but orientation dependency occurs
Solution Approach 1:
The patent uses dynamic beam rotation to sweep through all azimuth angles around the optical axis. This dynamic illumination replaces the static aperture hole method, collecting diffraction information from all orientations. By integrating signals from all azimuth angles, the system achieves orientation-independent observation of electromagnetic structures while maintaining high contrast.
Solution Approach 2:
The patent creates a universal observation method that works for all orientations of electromagnetic structures. Instead of requiring specific aperture positions for different orientations (Foucault method limitation), the rotating beam approach provides universal applicability by sampling all azimuth angles, making the observation capability independent of sample orientation.
3Measurement precision
If small angle aperture is used to observe electromagnetic structure, then contrast can be obtained, but spatial resolution is limited
Solution Approach 1:
The patent employs dynamic beam rotation to collect diffraction information at multiple angles without using a small aperture. The rotation enables the system to accumulate signal from all azimuth angles, achieving high contrast for electromagnetic structures while maintaining the full spatial resolution capability of the in-focus imaging system.
Solution Approach 2:
The patent implements continuous beam rotation through all azimuth angles, ensuring that the useful action of collecting diffraction information continues without interruption. This continuous sampling of all orientations provides both high contrast (through complete angular coverage) and high spatial resolution (through in-focus imaging), eliminating the need for aperture restrictions.
4Measurement precision
If conventional Lorenz microscopy is used, then electromagnetic structure can be observed, but electromagnetic field distribution cannot be visualized
Solution Approach 1:
The patent uses dynamic beam rotation to sweep through all azimuth angles, enabling the detection of electromagnetic field distributions in three-dimensional space. By collecting diffraction patterns at multiple orientations and integrating the information, the system reconstructs the electromagnetic field distribution, providing information that static conventional methods cannot capture.
Solution Approach 2:
The patent changes the illumination parameter by rotating the beam angle through all azimuth directions. This parameter change enables the system to probe electromagnetic structures from multiple orientations, allowing reconstruction of the electromagnetic field distribution in space. The angular parameter variation provides the additional information needed to visualize field distributions beyond what single-orientation methods can achieve.
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 high-resolution, in-focus observation of magnetic and dielectric materials, as well as biological and organic samples, with the ability to visualize electromagnetic field distributions, surpassing the limitations of conventional Lorenz microscopy techniques.
Implementation Method 1
adjusting a deflection action of each of the two stages of electron beam deflectors so that an irradiation angle to the sample is kept within a predetermined range
Implementation Method 2
an objective lens system for forming an image of the sample
Implementation Method 3
a diffraction pattern of the sample
Data Source
AI summary
An observation apparatus and method that avoids drawbacks of a Lorentz method and observes a weak scatterer or a phase object with in-focus, high resolution, and no azimuth dependency, by a Foucault method observation using a hollow-cone illumination that orbits and illuminates an incident electron beam having a predetermined inclination angle, an electron wave is converged at a position (height) of an aperture plate downstream of a sample, and a bright field condition in which a direct transmitted electron wave of the sample passes through the aperture plate, a dark field condition in which the transmitted electron wave is shielded, and a Schlieren condition in which approximately half of the transmitted wave is shielded as a boundary condition of both of the above conditions are controlled, and a spatial resolution of the observation image is controlled by selecting multiple diameters and shapes of the opening of the aperture plate.