Electron Microscope Edge Element for Isotropic Image Contrast
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Solution Overview
Problem
Existing electron microscope methods, such as using a knife edge to block diffracted waves, result in unidirectional image contrast, making it difficult to obtain isotropic image contrast from specimens with weak interactions, like biological materials.
Innovation Solution
An electron microscope with an edge element and control unit that adjusts the position of the diffraction spot relative to the edge element in the diffraction plane, allowing the electron beam to pass through a defined aperture, ensuring isotropic image contrast by varying the blocking direction of the diffracted wave.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a knife edge is used to block a part of the diffracted wave, then image contrast is improved, but the image contrast becomes unidirectional and anisotropic
Solution Approach 1:
The patent makes the previously static knife edge dynamic by enabling it to rotate around the direct beam. This allows the blocking direction to be changed dynamically, transforming the unidirectional contrast into isotropic contrast through rotational movement, thereby resolving the anisotropy problem while maintaining good image contrast
Solution Approach 2:
The patent employs periodic rotation of the knife edge around the direct beam to achieve isotropic image contrast. By rotating the edge element through different angular positions, the contrast enhancement effect is applied uniformly in all directions, converting the unidirectional contrast into isotropic contrast through periodic angular adjustment
2Measurement precision
If a knife edge blocks diffracted waves unidirectionally, then contrast is enhanced in one direction, but contrast uniformity in all directions deteriorates
Solution Approach 1:
The patent transforms the static unidirectional blocking into a dynamic system where the knife edge can rotate to different angular positions. This dynamic adjustment enables the contrast enhancement to be distributed uniformly in all directions, achieving isotropic image contrast while maintaining the contrast enhancement benefit
Solution Approach 2:
The patent uses an asymmetric knife edge geometry that, when rotated symmetrically around the direct beam, produces symmetric isotropic contrast. The asymmetric edge shape provides directional contrast enhancement at any given angle, but the rotational symmetry of the system overall produces uniform isotropic contrast across all directions
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 approach enables the acquisition of observation images with isotropic image contrast, improving interpretation and contrast uniformity across different directions, particularly for biological specimens with weak electron interactions.
Implementation Method 1
a transmission electron microscope (hereinafter, referred to as 'TEM') is a device which applies an electron beam accelerated by a high voltage to an observation object material and focuses the electron beam transmitted through the material into an enlarged image by means of an electromagnetic lens for microstructure imaging
Data Source
AI summary
An electron microscope for observation by illuminating an electron beam on a specimen, includes: an edge element disposed in a diffraction plane where a direct beam not diffracted by but transmitted through the specimen converges or a plane equivalent to the diffraction plane; and a control unit for controlling the electron beam or the edge element. The edge element includes a blocking portion for blocking the electron beam, and an aperture for allowing the passage of the electron beam. The aperture is defined by an edge of the blocking portion in a manner that the edge surrounds a convergence point of the direct beam in the diffraction plane. The control unit varies contrast of an observation image by shifting, relative to the edge, the convergence point of the direct beam along the edge while maintaining a predetermined distance between the convergence point of the direct beam and the edge.