Particle Beam Microscope Lens Excitation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for operating particle beam microscopes are time-consuming and require user intervention to focus the particle beam after changes in the electric potential of the object, due to unpredictable effects like hysteresis in the magnetic fields of the particle-optical lenses, making it difficult to achieve ideal focusing.
Innovation Solution
A method and system that generate a dependence between a manipulated variable and the excitation of the particle-optical lens, allowing users to adjust the lens excitation to achieve ideal focusing through a monotonic function, with smaller changes for closer excitation values and larger changes for larger deviations, facilitating quicker and more precise focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the user manually adjusts the focus by actuating a focus adjustment wheel, then the particle beam can be focused at the object, but the process is time-consuming and requires repeated user intervention
Solution Approach 1:
The system pre-calculates and stores the target values for the manipulated variable corresponding to ideal lens excitations for different electric potential combinations. When the electric potential is changed, the system automatically retrieves and applies the pre-determined target value, eliminating the need for time-consuming manual focus adjustment while maintaining precise focusing
Solution Approach 2:
The system continuously monitors the actual lens excitation and compares it with the target value. Based on this feedback, the system automatically adjusts the manipulated variable to minimize the deviation from the ideal focusing condition, ensuring precise focus is maintained even when electric potential changes
2Adaptability or versatility
If the electric potential of the object is changed to modify image contrast, then different structures become visible, but the particle beam focusing is disrupted and requires re-adjustment
Solution Approach 1:
The system pre-calculates target values for the manipulated variable corresponding to ideal lens excitations for various electric potential combinations. When the user changes the electric potential to observe different structures, the system automatically retrieves the pre-determined target value and adjusts the focusing, eliminating the need for manual re-adjustment and maintaining ease of operation
Solution Approach 2:
The system automatically compensates for focusing disruptions caused by electric potential changes without requiring user intervention. The controller autonomously determines the new target value based on the changed potential and adjusts the manipulated variable accordingly, allowing the system to serve itself in maintaining optimal focus
3Device complexity
If a linear dependence between the manipulated variable and lens excitation is used, then the control is simple, but large excitation deviations require excessive manipulation steps to correct
Solution Approach 1:
The system uses a non-linear, position-dependent dependence between the manipulated variable and lens excitation. The slope of this dependence varies dynamically based on the current excitation value: steeper slopes near the target enable rapid correction of large deviations, while shallower slopes near the target allow precise final adjustment. This dynamic control characteristic simultaneously achieves fast convergence and high precision without excessive manipulation steps
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 allows for faster and more precise setting of the ideal excitation of the particle-optical lens, reducing the time and effort required for focusing the particle beam, even in cases where the current excitation significantly differs from the ideal, and ensures precise focusing with minimal user intervention.
Implementation Method 1
The particle beam is generated by a particle source and accelerated
Implementation Method 2
it is focused at the object by an objective lens
Implementation Method 3
Electric fields are present between the objective lens and the object in some particle beam microscopes in order to provide a lens effect for focusing the particle beam
Implementation Method 4
due to unpredictable effects like hysteresis in the magnetic fields of the particle-optical lenses
Implementation Method 5
secondary electrons or backscattered electrons, generated by the incident electron beam at the object
Implementation Method 6
secondary electrons or backscattered electrons, generated by the incident electron beam at the object
Data Source
AI summary
A method for operating a particle beam microscope includes: setting potentials of a particle source and an object; directing a particle beam onto the object; setting an excitation of a particle-optical lens; generating a dependence between a manipulated variable and the excitation so that the excitation is representable as a monotonic function dependent on the manipulated variable; changing the manipulated variable via an actuating element to focus the particle beam at the object; and determining a target value of the manipulated variable in a manner dependent on the set potentials. The target value virtually corresponds to an ideal excitation of the lens. The particle beam in the case of the ideal excitation is focused at the object. The absolute value of the first derivative of the function in a value range containing the target value is less than in the case of values lying outside of this value range.