Automated Phase Plate Alignment in Electron Microscopy
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Solution Overview
Problem
Current methods for aligning phase plates in electron microscopes are cumbersome and expose biological samples to excessive electron radiation, limiting measurement times and accuracy due to manual adjustment and high radiation exposure.
Innovation Solution
An automated image analysis method is used to align the phase plate by recording and evaluating images taken at different focal lengths, allowing for precise correction of the phase plate's position with minimal radiation exposure and increased accuracy, enabling longer measurement times and reduced sample damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual alignment of the phase plate is performed, then the operator can adjust the position based on visual inspection, but the process becomes cumbersome and requires many test steps exposing the sample to excessive electrons
Solution Approach 1:
The patent replaces manual mechanical adjustment and visual inspection with an automated optical detection system. The method uses image recording and automated analysis to detect the phase plate position, substituting the mechanical manual tracking process with an automated optical-mechanical system that reduces harmful electron exposure while maintaining alignment precision.
Solution Approach 2:
The patent creates an optical copy (image) of the phase plate position and uses this copy for analysis instead of directly manipulating the physical phase plate through multiple test steps. By recording images at different focal lengths and analyzing them computationally, the system determines the correct position without requiring the sample to be exposed to electrons during the alignment process.
2Ease of operation
If multiple test images are recorded during manual positioning, then the operator can determine optimal phase plate position, but the sample becomes unusable due to excessive electron exposure
Solution Approach 1:
The patent uses periodic action by recording images at specific, predetermined focal lengths (first and second focal lengths) rather than continuously during manual adjustment. This periodic imaging approach, combined with automated analysis, eliminates the need for continuous electron exposure during alignment while maintaining ease of operation and sample usability.
Solution Approach 2:
The system performs self-service by automatically analyzing the recorded images to determine phase plate position and generate correction values, eliminating the need for operator intervention and multiple test steps. The automated image analysis and correction value determination reduce electron exposure while maintaining alignment capability.
3Measurement precision
If the phase plate is readjusted manually during measurement, then positioning accuracy can be maintained, but measurement time is limited to approximately 30 minutes
Solution Approach 1:
The patent performs preliminary action by determining the phase plate position and generating correction values before the actual measurement process begins. The automated alignment method establishes the correct position in advance using minimal electron exposure, eliminating the need for frequent readjustments during the measurement period and enabling longer measurement times while maintaining positioning accuracy.
4Object-affected harmful factors
If automated image analysis is used to determine correction values, then the number of images required for alignment is reduced, but complex image processing is required
Solution Approach 1:
The patent uses parameter changes by varying the focal length of the lens to create images at different focus states. This parameter change (focal length) provides the necessary information for automated analysis to determine phase plate position and generate correction values, reducing electron exposure while managing system complexity through a well-defined optical parameter variation.
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
The automated method significantly reduces the number of images required for alignment, increases accuracy, and makes phase microscopy more user-friendly, allowing less experienced operators to use cryo-electron microscopy with reduced risk of sample damage.
Implementation Method 1
A lens is defocused with respect to a phase plate (6)... Two images (11, 12) are recorded of a hole (9) in the phase plate (6)
Data Source
AI summary
The invention relates to a method for aligning a phase plate (6) inside an electron microscope (1), wherein the electron microscope (1) comprises an electron beam source (3) for generating an electron beam (5) and at least one lens (4) for focusing the electron beam (5), wherein by means of the phase plate (6) a defined phase shift is added to parts of the electron beam (5), comprising the following method steps: relative alignment of the phase plate (6) in relation to a focal plane (B) of the lens (4), lateral positioning of the phase plate (6) inside the focal plane (B), wherein at least one image is taken by means of an image recording unit and by means of an automated image analysis method a correction value (K) and/or a blur value is determined, modification of the lateral position of the phase plate (6) in dependence of the correction value (K) and/or modification of the alignment of the phase plate (8) in relation to the focal plane (B) in dependence of the blur value.