Electron Microscope Image Acquisition Reducing Diffraction Contrast
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Solution Overview
Problem
Electron microscopes face challenges in observing samples due to diffraction contrast phenomena such as fringes of equal thickness and fringes of equal inclination, which obstruct image acquisition, especially at moderate and low magnifications, and are difficult to eliminate, especially when observing crystalline or polycrystalline samples.
Innovation Solution
A method of image acquisition in electron microscopes that involves obtaining plural images by varying the direction of incidence of the electron beam with respect to the sample, either by tilting the sample or deflecting the electron beam, and accumulating these images to reduce the effects of diffraction contrast without affecting the contrast produced by differential phase contrast methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If diffraction contrast phenomena are observed in electron microscope images, then sample thickness and tilt information can be obtained, but the observation of sample features is obstructed
Solution Approach 1:
The patent changes the incident angle parameter of the electron beam relative to the sample. By acquiring images at multiple different incident angles and accumulating them, the diffraction contrast phenomena which vary with angle are reduced, while the sample feature information remains consistent and is enhanced through accumulation.
2Loss of information
If trial-and-error tilting conditions are used to minimize diffraction contrast, then observation clarity improves, but time consumption increases
Solution Approach 1:
The patent performs preliminary action by automatically acquiring images at multiple preset incident angles without requiring manual trial-and-error adjustment. The system pre-defines multiple angle positions and automatically executes the acquisition and accumulation process, eliminating the time-consuming manual optimization step.
Solution Approach 2:
The patent implements self-service through automated image accumulation. The system automatically acquires multiple images at different incident angles, processes them through accumulation calculation, and generates the final reduced-diffraction image without requiring continuous manual intervention or optimization by the operator.
3Object-generated harmful factors
If multiple images are accumulated by varying incident direction, then diffraction contrast effects are reduced, but image acquisition time increases
Solution Approach 1:
The patent employs periodic action by acquiring images at multiple discrete incident angle positions in a systematic sequence. The electron beam is directed at the sample at predetermined angle intervals, and the images are accumulated in order, providing a structured approach that reduces diffraction effects while managing acquisition time through efficient periodic sampling.
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 allows for the generation of images that are less affected by diffraction contrast, enabling clearer observation of sample features without the need for trial-and-error tilting conditions, and can be applied to both scanning transmission electron microscopy and transmission electron microscopy.
Implementation Method 1
the electron beam transmitted through a sample is deflected by the electromagnetic field within the sample, and this deflection is detected as a beam shift on the detection surface of a detector
Implementation Method 2
Where a crystalline sample is observed with a transmission electron microscope or a scanning transmission electron microscope, there occurs diffraction contrast according to variations in the thickness or tilt of the sample
Data Source
AI summary
There is provided a method of image acquisition capable of reducing the effects of diffraction contrast. This method of image acquisition is implemented in an electron microscope for generating electron microscope images with electrons transmitted through a sample. The method starts with obtaining the plural electron microscope images while causing relative variations in the direction of incidence of an electron beam with respect to the sample. An image is generated by accumulating the plural electron microscope images.