Electron Microscope Frost Prevention via Dual-Mode Image Feedback
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Solution Overview
Problem
Current electron microscope techniques fail to accurately evaluate the appropriateness of samples embedded in ice for observation, leading to potential damage from the electron beam and frost formation, which affects image quality.
Innovation Solution
A charged particle beam device and electron microscope system equipped with a sample stage for cooling, a vacuum system with a cold trap to manage moisture, and detectors for secondary and transmitted electrons, allowing for the acquisition and analysis of secondary electron images and transmitted electron images to assess the sample's state and determine its suitability for observation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the sample is rapidly frozen and embedded in ice without chemical fixation, then the original structure of the biological tissue is retained, but the sample may not be in an appropriate frozen state for observation, leading to structure exposure and damage by electron beam
Solution Approach 1:
The invention implements a feedback mechanism by automatically evaluating the sample's frozen state using image processing of secondary electron images and transmitted electron images. The system determines appropriate frozen state, frost attachment, and structure exposure, then provides feedback to control the observation process, ensuring reliable and stable observations while maintaining the original tissue structure.
Solution Approach 2:
The invention performs preliminary evaluation of the sample's frozen state before actual observation. By assessing the appropriate frozen state, frost attachment, and structure exposure in advance, the system prepares the optimal conditions for observation, preventing potential damage during the imaging process.
2Ease of operation
If the electron microscope observes the sample without evaluating the frozen state, then the observation process is simple, but frost attachment and structure exposure cannot be clearly determined, affecting image quality
Solution Approach 1:
The invention enables the system to self-evaluate the sample's frozen state automatically. The image processing unit analyzes secondary electron images and transmitted electron images to determine appropriate frozen state, frost attachment, and structure exposure without requiring manual intervention, thus maintaining operational simplicity while achieving precise sample state evaluation.
Solution Approach 2:
The invention utilizes differences in image characteristics (analogous to color changes) between secondary electron images and transmitted electron images to detect and evaluate the sample's frozen state, frost attachment, and structure exposure. These image variations provide visual indicators for automatic evaluation.
3Reliability
If the sample is observed in a vacuum environment, then the electron beam can penetrate the sample, but moisture in the vicinity may freeze and form frost on the sample surface
Solution Approach 1:
The invention performs preliminary evaluation to detect frost attachment on the sample surface before actual observation. By identifying frost formation in advance through image processing, the system can take preventive or corrective actions to remove or prevent frost, ensuring clear imaging without frost-related artifacts.
Solution Approach 2:
The invention implements a feedback mechanism that continuously monitors the sample surface for frost attachment during observation. When frost is detected, the system provides feedback to adjust observation conditions or activate frost removal mechanisms, maintaining reliable electron beam transmission while preventing harmful frost formation.
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 high-accuracy and stable observation of samples by determining the sample's frozen state and preventing frost formation, ensuring the preservation of the original structure and maintaining a favorable observation condition.
Implementation Method 1
the sample stage includes cooling means for cooling the sample
Implementation Method 2
the vacuum system includes a cold trap that sucks moisture in a vicinity of the sample
Implementation Method 3
a secondary electron detector that detects a secondary electron emitted from the sample by irradiation with the charged particle beam
Implementation Method 4
a transmitted electron detector that detects a transmitted electron through the sample by the irradiation with the charged particle beam
Data Source
AI summary
Provided is an electron microscope with which a sample can be observed stably and with high accuracy. The electron microscope comprises: a sample stage; an electron optical system that scans an electron beam over a sample; a vacuum system that maintains the sample stage and the electron optical system in a vacuum; a secondary electron detector that detects secondary electrons emitted from the sample; transmitted electron detectors that detect transmitted electrons that have transmitted through the sample; and a control device that obtains a secondary electron image and a transmitted electron image on the basis of the secondary electrons and the transmitted electrons detected by the secondary electron detector and the transmitted electron detectors and stores the secondary electron image and the transmitted electron image. The sample stage is provided with cooling means for cooling the sample. The vacuum system is provided with a cold trap that sucks moisture from around the sample and a vacuum gauge that measures the degree of vacuum of the vacuum system.