Electron Microscope Crossover Stability via Voltage Ratio Control
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Solution Overview
Problem
Conventional electron microscopes face challenges in maintaining electron beam brightness and crossover position stability when accelerating voltage or extraction voltage is modified, leading to suboptimal imaging and energy loss spectroscopy performance.
Innovation Solution
An electron microscope design with a controller that maintains a constant ratio between the voltage applied to the first electrode and the initial stage of acceleration electrode, and optionally includes a monochromator and deflector, ensures the lens action and crossover position remain constant even when accelerating or extraction voltage is altered, thereby maintaining electron beam brightness and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the accelerating voltage is modified, then the operational flexibility and processing capability are improved, but the crossover position stability deteriorates
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the voltage applied to the first electrode in response to changes in accelerating voltage. The control unit modifies the first electrode voltage proportionally to the accelerating voltage change, thereby maintaining a constant lens action and stabilizing the crossover position while allowing operational flexibility.
Solution Approach 2:
The patent implements feedback control where the control unit continuously monitors the accelerating voltage and automatically adjusts the first electrode voltage to compensate for changes. This closed-loop control ensures that the crossover position remains stable even when the accelerating voltage is modified, resolving the contradiction between adaptability and stability.
2Illumination intensity
If the extraction voltage is modified, then the electron beam brightness is improved, but the lens action stability deteriorates
Solution Approach 1:
The patent applies parameter changes by adjusting the first electrode voltage in proportion to the extraction voltage. When the extraction voltage is modified to improve electron beam brightness, the control unit simultaneously modifies the first electrode voltage to maintain a constant lens action, thereby preventing deterioration of lens action stability.
3Productivity
If the accelerating voltage is modified, then the processing capability is improved, but the instrument shutdown requirement increases
Solution Approach 1:
The patent implements continuity of useful action by enabling voltage modifications during operation without requiring instrument shutdown. The control unit dynamically adjusts the first electrode voltage in real-time to compensate for accelerating voltage changes, allowing the electron microscope to maintain stable crossover position and continue processing without interruption, thereby eliminating time loss from shutdowns.
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 solution allows for consistent electron beam brightness and high-resolution imaging and spectroscopy across varying voltages, enhancing the microscope's operational flexibility and processing capability without the need for instrument shutdowns.
Implementation Method 1
a lens action is produced between this first electrode and the initial stage of acceleration electrode of the plural stages of acceleration electrodes; The lens action produced between the first electrode and the initial stage of acceleration electrode forms a crossover of the electron beam
Implementation Method 2
an acceleration tube which has plural stages of acceleration electrodes stacked one above the other and which is operative to accelerate the electron beam
Implementation Method 3
a monochromator for monochromatizing the electron beam; an energy filter (which is an electron beam splitter) and an energy-selecting slit
Data Source
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AI summary
There is provided an electron microscope in which a crossover position can be kept constant. The electron microscope (100) includes: an electron source (110) for emitting an electron beam; an acceleration tube (170) having acceleration electrodes (170a-170f) and operative to accelerate the electron beam; a first electrode (160) operative such that a lens action is produced between this first electrode (160) and the initial stage of acceleration electrode (170a); an accelerating voltage supply (112) for supplying an accelerating voltage to the acceleration tube (170); a first electrode voltage supply (162) for supplying a voltage to the first electrode (160); and a controller (109b) for controlling the first electrode voltage supply (162). The lens action produced between the first electrode (160) and the initial stage of acceleration electrode (170a) forms a crossover (CO2) of the electron beam. The controller (109b) controls the first electrode voltage supply (162) such that, if the accelerating voltage is modified, the ratio between the voltage applied to the first electrode (160) and the voltage applied to the initial stage of acceleration electrode (170a) is kept constant.