Confocal STEM Image Acquisition via Digital Diffraction Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing confocal STEM imaging systems face difficulties in obtaining accurate images without special detector apertures and synchronized imaging system scanning, leading to challenges in controlling sample drift and maintaining precise positioning, especially when scanning on a sub-Angstrom scale.
Innovation Solution
The method involves recording diffraction images with a CCD camera in synchronism with scanning, correcting the center positions of these images, and extracting only the innermost portions to reproduce confocal STEM images, thereby dispensing with the need for special detector apertures and imaging system scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pinhole-type aperture is used in the imaging system, then confocal image quality is improved, but device complexity increases and ease of operation deteriorates
Solution Approach 1:
The patent extracts the confocal imaging function from the optical imaging system and relocates it to the detector processing stage. By using a CCD camera to capture diffraction patterns and then extracting only the central portion (0-5 pixels) through software processing, the system eliminates the need for physical pinhole apertures and complex optical components, thereby reducing device complexity while maintaining confocal image quality
Solution Approach 2:
The patent replaces the mechanical pinhole aperture with a digital processing approach. Instead of using physical optics to block off-axis electrons, the system uses software algorithms to extract and process only the central region of diffraction patterns captured by the CCD camera, substituting mechanical filtering with computational filtering
2Measurement precision
If the imaging system is scanned to synchronize with sample scanning, then confocal image accuracy is improved, but ease of operation deteriorates and device complexity increases
Solution Approach 1:
The patent implements self-service by having the system automatically extract and process diffraction patterns without requiring manual synchronization or complex operational procedures. The automated extraction of central portions (0-5 pixels) from CCD captured images and the automatic centering algorithm eliminate the need for manual scanning coordination, significantly improving ease of operation while maintaining accuracy
3Measurement precision
If sample scanning is performed on sub-Angstrom scale, then image precision is improved, but sample drift control becomes difficult and manufacturing precision deteriorates
Solution Approach 1:
The patent introduces diffraction patterns as an intermediary to achieve precise positioning. Instead of directly scanning the sample and relying on mechanical positioning systems that suffer from drift, the system uses diffraction patterns captured by the CCD camera as an intermediary reference. The automatic centering of these patterns provides a stable reference frame that compensates for sample drift and mechanical imperfections, thereby improving positioning precision at sub-Angstrom scales
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 acquisition of confocal STEM images using ordinary equipment, eliminating the need for special devices and reducing sample drift issues, while maintaining image precision.
Implementation Method 1
When passing through the thin-film sample, the beam interacts with the sample. As a result, the orbit or phase may be varied or the beam may interact with the atoms in the sample, thus producing energy loss.
Implementation Method 2
An electron beam extracted from an electron gun is accelerated by an acceleration tube and made to hit a thin-film sample. Impinging electrons emitted from an electron gun are focused onto a sample by condenser lenses.
Implementation Method 3
Electrons transmitted through the sample are again focused at the position of an aperture by an imaging lens.
Implementation Method 4
The aperture permits only a part of the central portion of the focused electron beam on the sample to pass through.
Implementation Method 5
The central portion is detected by a detector.
Implementation Method 6
A piezo actuator 3 moves the sample 10 in a direction perpendicular to the optical axis.
Implementation Method 7
The sample is moved in three dimensions by a goniometer 9.
Data Source
AI summary
Method and system to obtain confocal STEM images. Arithmetic and control device extracts diffraction images respectively corresponding to successive pixel positions from the images stored in the memory, selects and corrects center positions of the extracted diffraction images, creates an image set having diffraction information in which the center positions of the diffraction images have been corrected and aligned, selects only innermost portions of the diffraction images of the created image set, and reproduces STEM images from the diffraction images, thus obtaining a confocal STEM image.