Direct Electron Detector Peak Displacement for TEM Sensor Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High intensity peaks in TEM images, such as diffraction patterns and EELS spectra, can cause damage to sensors like CCD or CMOS cameras due to saturation and prolonged overexposure, leading to noise and dead pixels.
Innovation Solution
The method involves displacing the high intensity peak on the sensor by repositioning the image, either mechanically or using electrostatic/magnetic deflection, to distribute the high intensity over a larger area, reducing local dose and preventing sensor degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the high intensity peak is imaged directly on the sensor, then the image quality and signal strength are improved, but the sensor is damaged due to saturation and prolonged overexposure
Solution Approach 1:
The patent applies dynamics by making the image position on the sensor movable rather than fixed. The high intensity peak is dynamically repositioned across different sensor locations during acquisition, allowing the same sensor to capture the peak at multiple positions over time. This dynamic approach distributes the harmful intensity exposure while maintaining complete image data acquisition.
Solution Approach 2:
The patent transitions from a static two-dimensional image capture to a dynamic three-dimensional approach by adding the time dimension. The peak position varies over time across the sensor surface, effectively using the time dimension to distribute spatial exposure. This allows the system to maintain high signal strength while preventing localized sensor damage through temporal distribution of the intensity load.
2Productivity
If the image is kept stationary on the sensor, then the acquisition process is simple and fast, but the sensor degrades due to concentrated high intensity exposure
Solution Approach 1:
The patent implements dynamics by introducing motion to the image position on the sensor during acquisition. Rather than keeping the image stationary, the system dynamically shifts the peak position across different sensor regions, thereby distributing the cumulative exposure and preventing localized degradation while maintaining acquisition efficiency.
Solution Approach 2:
The patent applies preliminary action by pre-planning the peak displacement trajectory before acquisition. The system determines in advance how the peak will be repositioned across the sensor, allowing for optimized acquisition paths that protect the sensor while maintaining productivity. This preparatory positioning strategy ensures sensor longevity without compromising acquisition speed.
3Object-affected harmful factors
If the high intensity peak is dispersed over a larger area, then sensor damage is reduced, but the peak intensity is reduced which may affect measurement precision
Solution Approach 1:
The patent resolves this contradiction by adding the time dimension to the spatial distribution problem. Instead of dispersing the peak over a larger area at any given moment (which would reduce signal strength), the system concentrates the peak at full intensity at each instant but moves it across different locations over time. This temporal-spatial distribution maintains peak signal strength while distributing the cumulative exposure damage across multiple sensor regions.
Solution Approach 2:
The patent uses dynamics to maintain high peak intensity while preventing sensor damage through motion. The peak remains concentrated and intense at each moment, preserving measurement precision, but its position changes dynamically over time. This dynamic concentration and relocation strategy ensures both signal strength and sensor protection are achieved simultaneously.
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 minimizes sensor damage by limiting the exposure time of any single sensor location to the high intensity, thereby reducing noise and extending the lifespan of the imaging device.
Implementation Method 1
Diffraction occurs because the periodic structure of a crystalline solid acts as a diffraction grating, scattering the electrons in a predictable manner.
Implementation Method 2
Some electrons are diffracted, some electrons loose energy and some electrons are absorbed.
Implementation Method 3
some electrons loose energy... To that end thicknesses between, for example, 30 nm (for samples comprising many high-Z atoms, such as semiconductor material or metallic samples) and 200 nm (for biological samples) are routinely used
Data Source
AI summary
A method of using a direct electron detector in a TEM, in which an image with a high intensity peak, such as a diffractogram or an EELS spectrum, is imaged on said detector. As known the high intensity peak may damage the detector. To avoid this damage, the center of the image is moved, as a result of which not one position of the detector is exposed to the high intensity, but the high intensity is smeared over the detector, displacing the high intensity peak before damage results.