Transmission Electron Microscope Bright-Field Dark-Field Imaging
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Solution Overview
Problem
Current transmission electron microscopes have limitations in analyzing samples over a wide range with high resolution, as they often require narrow measurement ranges and longer measurement times due to the need for precise condensation of the electron beam.
Innovation Solution
A transmission electron microscope design that includes an irradiation unit for emitting a parallel electron beam at a predetermined incident angle, a sample holding unit, an aperture unit with an opening, an image forming lens, an image capturing unit for bright-field and dark-field imaging, and an analysis unit that analyzes the images to classify the sample based on electron beam intensity at various angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electron beam is precisely condensed to achieve high resolution, then measurement precision is improved, but the measurement range is limited and measurement time increases
Solution Approach 1:
The patent divides the electron beam imaging into multiple independent channels: a bright-field image capturing unit for transmitted electrons and a dark-field image capturing unit for scattered electrons. This segmentation allows simultaneous acquisition of multiple types of information without requiring sequential measurements, thereby reducing total measurement time while maintaining high resolution through the precise beam condensation in each channel.
Solution Approach 2:
The patent introduces an angular dimension by capturing electrons at different scattering angles through the dark-field imaging system. This adds a new dimension to the analysis beyond simple transmission intensity, enabling simultaneous wide-range survey and high-resolution analysis by utilizing the angular distribution of electrons to identify crystal structures and grain boundaries across the entire sample area.
2Measurement precision
If the electron beam is precisely condensed to achieve high resolution, then measurement precision is improved, but the measurement range is limited
Solution Approach 1:
By segmenting the detection system into bright-field and dark-field channels, the patent enables simultaneous coverage of the entire sample area through the dark-field imaging of scattered electrons while maintaining high resolution through the precise beam condensation in the bright-field channel. The segmentation allows each channel to optimize for its specific function without compromising the other.
Solution Approach 2:
The patent utilizes the angular dimension of electron scattering to extend the measurement range. By capturing electrons at various scattering angles in the dark-field mode, the system can map the entire sample area and identify crystal grains and boundaries across wide regions, effectively adding spatial coverage without sacrificing resolution.
3Measurement precision
If conventional electron beam condensation is used, then high resolution is achieved, but the system complexity increases due to precise control requirements
Solution Approach 1:
The patent segments the beam control and detection functions into distinct units: a bright-field imaging unit for direct transmission and a dark-field imaging unit for scattered electrons. This segmentation allows each unit to have optimized, simpler control mechanisms rather than requiring a single complex system to handle all imaging requirements, thereby reducing overall system complexity while maintaining high resolution.
Solution Approach 2:
The patent creates a multi-functional imaging system where the same electron beam can be used for both bright-field and dark-field imaging by controlling the aperture and detection channels. This universality reduces the need for separate beam control systems for different imaging modes, simplifying the overall device while maintaining the capability to achieve high resolution through precise beam condensation when needed.
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 analysis of samples over a wide range with high resolution and reduced measurement time by emitting the electron beam over a wide region and capturing images at multiple angles, allowing for efficient classification of crystal, amorphous, and crystal grain regions.
Implementation Method 1
A sample transmits or scatters the emitted electron beam
Implementation Method 2
an image forming lens that is located downstream in a traveling direction of the electron beam with respect to the opening of the aperture unit and that forms an image of the electron beam selected by the aperture unit
Data Source
AI summary
According to one embodiment, a transmission electron microscope includes an irradiation unit that is configured to irradiate a sample with a parallel electron beam at a predetermined incident angle, a sample holding unit that is configured to hold the sample, an aperture unit that is located downstream in a traveling direction of the electron beam transmitted the sample or scattered by the sample and that has an opening, an image forming lens that is located downstream in the traveling direction of the electron beam with respect to the opening of the aperture unit and that forms an image of the electron beam selected by the aperture unit, an image capturing unit that is located downstream in the traveling direction of the electron beam with respect to the image forming lens, that captures a bright-field image and a dark-field image formed by the image forming lens, and that has an imaging surface, and an analysis unit that analyzes the sample based on the bright-field image and the dark-field image.