Electron Sensor with Guard Electrodes for Cross-Talk Reduction
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Solution Overview
Problem
Current electron sensors in electron microscopy are susceptible to damage from high-energy electron beams, suffer from charge sharing and limited spatial resolution due to 'cross-talk', and have inadequate dynamic range, leading to image quality degradation and increased exposure times, especially when capturing diffraction patterns with high electron current densities.
Innovation Solution
An electron sensor design featuring a substrate with parallel front and rear planes, input electrodes separated by guard electrodes, and energy measurement electrodes at different depths, connected via high conductivity tracks, allowing precise energy measurement and reduced cross-talk, enabling direct electron detection with high spatial and energy resolution and increased dynamic range without exposing electronic circuitry to radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrons are absorbed in different directions including depth and width of the electron sensor, then the sensor can detect electrons effectively, but the effective resolution is limited due to charge sharing and cross-talk between adjacent pixels
Solution Approach 1:
The patent introduces a depth dimension by placing collecting electrodes at different depths within the substrate. This vertical stratification allows the system to resolve charge sharing in the lateral direction by detecting the depth distribution of electron-hole pairs, effectively converting a 2D resolution problem into a 3D detection problem that eliminates cross-talk between adjacent pixels.
Solution Approach 2:
The substrate is divided into multiple detection regions with collecting electrodes positioned at different depths. Each depth level acts as an independent detection layer, segmenting the charge collection process vertically. This segmentation allows the system to attribute signals to specific lateral positions without interference from adjacent pixels, resolving the charge sharing issue.
2Reliability
If indirect detection with scintillator is used to avoid radiation damage, then the electronic circuit is protected from high-energy electrons, but the sensor operation is affected by charge sharing and cross-talk leading to image quality deterioration
Solution Approach 1:
The patent extracts the electronic circuitry from the radiation exposure zone by placing it outside the substrate area subjected to high-energy electron beams. The substrate itself acts as the radiation-resistant detection medium, while the electronics are positioned in a protected region, eliminating both radiation damage and charge sharing issues simultaneously.
Solution Approach 2:
The substrate serves as an intermediary between the incident electrons and the collecting electrodes. It converts high-energy electrons into electron-hole pairs and guides the charge carriers to the collecting electrodes through internal electric fields, mediating the detection process in a way that prevents direct electron-circuit interaction and eliminates cross-talk.
3Area of stationary object
If pixels are placed closer to improve sensor compactness, then the sensor size is reduced, but charge sharing between adjacent pixels increases limiting spatial resolution
Solution Approach 1:
By adding the depth dimension for charge collection, the patent enables pixels to be placed closer together in the lateral plane without increasing cross-talk. The vertical separation of collecting electrodes at different depths provides an additional degree of freedom that isolates adjacent lateral pixels, allowing compact sensor design while maintaining high spatial resolution.
4Measurement precision
If exposure time is increased to improve signal-noise ratio in indirect detection, then image quality improves, but biological samples alter their atomic structure during observation
Solution Approach 1:
The patent extracts the detection function from the scintillator conversion process and implements direct electron detection in the substrate. This eliminates the need for prolonged exposure times associated with indirect detection, allowing rapid image acquisition that preserves the structural integrity of radiation-sensitive biological samples while maintaining high signal quality.
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 sensor effectively reduces cross-talk, enhances spatial resolution, and increases dynamic range, allowing for high-quality two-dimensional image formation and energy measurement without radiation damage, suitable for TEM, SEM, and STEM applications.
Implementation Method 1
the electron sensor comprises a substrate, with a front plane and a rear plane parallel to one another, which is intended to absorb at least one electron of an electron beam... and this electron is susceptible of generating an electric charge of free electron-hole (e-h) pairs in said substrate
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
This invention is an electron sensor (1) and a system with a plurality of electron sensors (1) for electron microscopy using an electron microscope. More specifically, the electron microscope generates an electron beam (10) that comprises at least one electron that impacts on a lateral reception surface (3) of said electron sensor (1) and this generates an electrical charge of electron-hole (e-h) pairs that are detected and/or measured by at least electrodes (6, 7) linked to an electric circuit unit (12) to form a high dynamic range image (11) and measure the energy of the electrons impacting each pixel of the image.