Electron Microscope Image Superimposition via Reverse Scanning
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Solution Overview
Problem
Existing electron microscope image acquisition methods face challenges in achieving high accuracy when superimposing images due to positional deviations, requiring repetitive scanning with concomitant positional deviations and subsequent drift correction.
Innovation Solution
The method involves raster scanning a sample with an electron probe to obtain two images, where the first image is scanned in one direction and then moved perpendicular to it, and the second image is scanned in the same direction but moved opposite to the second direction, allowing for precise correction of positional deviations between the two images for high-accuracy superimposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple images are acquired by repetitive scanning of the same region, then image quality is improved through superimposition, but positional deviations occur between images
Solution Approach 1:
The patent applies reverse scanning direction to reduce positional deviations. Specifically, odd-numbered images are scanned in a forward direction while even-numbered images are scanned in a reverse direction. This inversion of scanning direction compensates for drift accumulation, allowing images to be superimposed with higher positional accuracy despite repetitive scanning of the same region.
2Measurement precision
If drift correction is applied to adjust overlap position, then positional deviation is reduced, but image acquisition time increases
Solution Approach 1:
The patent performs preliminary drift correction by alternating scanning directions before final image superimposition. By scanning odd images in one direction and even images in the opposite direction, the system proactively compensates for drift effects in advance, reducing the need for complex post-acquisition correction and minimizing additional acquisition time.
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 precise alignment and superimposition of electron microscope images, reducing positional deviations and improving image quality by correcting distortions, resulting in a high-quality accumulation image.
Implementation Method 1
an electron source emitting an electron beam
Implementation Method 2
an illumination lens system for focusing the emitted electron beam into the electron probe
Implementation Method 3
a deflector for deflecting the electron beam to scan the sample with the electron probe
Data Source
AI summary
An image acquisition method is provided for use in an electron microscope for scanning a sample by an electron probe and acquiring a scanned image. The method includes the steps of: raster scanning a region of the sample under observation with the electron probe and obtaining a first scanned image; raster scanning the region under observation with the electron probe and obtaining a second scanned image; and superimposing the first and second scanned images over each other. In the step of obtaining the first scanned image, each one of scan lines is drawn with the electron probe in a first direction and then moved in a second direction perpendicular to the first direction. In the step of obtaining the second scanned image, each one of the scan lines is drawn with the electron probe in the first direction and then moved in a third direction opposite to the second direction.