Electron Microscope Coil Layout for Extended Magnetic Compensation
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Solution Overview
Problem
Existing magnetic field compensation systems for electron microscopes are bulky, inflexible, and limited to a small spatial volume, leading to increased electromagnetic interference and reduced measurement accuracy.
Innovation Solution
The apparatus and method provide a compact and flexible magnetic field compensation system using a pair of compensation coils arranged along the central axis of the electron microscope, with additional coils in orthogonal directions, creating an elongated compensation volume that can extend several meters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If a large-volume compensation structure is used to provide magnetic field compensation, then the compensation volume is sufficiently large, but the device becomes bulky and inflexible
Solution Approach 1:
The patent divides the compensation structure into multiple independent coil units (first coil unit, second coil unit, third coil unit, fourth coil unit) arranged along the central axis. Each coil unit can be independently controlled and optimized, allowing the system to achieve large-volume compensation without requiring a single bulky structure. This segmentation enables flexible arrangement and reduces overall device complexity.
Solution Approach 2:
The patent transitions from traditional planar coil arrangements to a three-dimensional linear arrangement along the central axis of the electron microscope. By distributing coil units at different positions (first, second, third, fourth units) along the axial dimension, the system creates an elongated compensation volume that extends along the beam path, achieving large-volume compensation in the longitudinal direction rather than requiring a bulky transverse structure.
2Device complexity
If a compact coil arrangement is used to reduce device size, then the device becomes more flexible, but the compensation volume becomes limited to a small spatial region
Solution Approach 1:
The compensation system is divided into multiple coil units (first, second, third, fourth coil units) positioned at different locations along the central axis. This segmentation allows each unit to contribute to the overall compensation field, extending the effective compensation volume along the axial direction without requiring each individual unit to be large or complex.
Solution Approach 2:
The patent exploits the longitudinal dimension along the central axis to extend the compensation volume. By arranging coil units at different axial positions (with the second and third units positioned at a distance from the first and fourth units respectively), the system creates an elongated compensation region that covers a larger spatial volume without increasing the transverse footprint or individual coil complexity.
3Device complexity
If magnetic field compensation is provided only at a point-like volume, then the device is compact, but electromagnetic interference increases rapidly outside this small volume
Solution Approach 1:
The patent divides the compensation function across multiple coil units positioned at different axial locations. This segmentation creates overlapping compensation fields that extend along the beam path, ensuring that electromagnetic interference is suppressed over an extended volume rather than just at a single point, thereby protecting the electron trajectory throughout its journey.
Solution Approach 2:
The compensation volume is extended along the longitudinal axis by positioning coil units at different distances from the sample. This creates a distributed compensation field that covers a larger axial range, reducing electromagnetic interference along the entire electron beam path rather than confining compensation to a narrow transverse region.
4Volume of stationary object
If additional coil units are added to extend compensation along the central axis, then the compensation volume increases, but the device complexity increases
Solution Approach 1:
The compensation system is segmented into modular coil units that can be independently designed, positioned, and controlled. This modularity allows the system to achieve extended compensation volume through simple addition of standardized units rather than designing a single complex structure, thereby managing device complexity through standardization and independence of components.
Solution Approach 2:
The patent extends the compensation volume primarily along the axial dimension by positioning coil units at different distances from the sample along the central axis. This approach achieves volume extension in the most critical direction (along the beam path) without requiring proportional increases in transverse dimensions or overall structural complexity.
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 configuration significantly reduces magnetic interference, allowing for high-resolution imaging and analysis over a larger area without the need for bulky compensation structures, thereby enhancing measurement accuracy and flexibility.
Implementation Method 1
a feedback sensor captures the magnetic interference field, for example the earth's magnetic field, in the vicinity of the object to be protected, and transmits this signal to a control unit. Based on the sensor signals, the control unit calculates a compensation current which is fed to the compensation coils. The latter will then generate a magnetic field which, ideally, destructively overlaps the interference field
Implementation Method 2
a device for guiding the electrically charged particles along a central axis MZ towards the chamber
Data Source
AI summary
The present invention relates to an apparatus and a method for imaging and/or analyzing and/or processing a sample by means of electrically charged particles, for example using a transmission or scanning electron microscope. The object of the invention is to reduce the influence of magnetic fields.For this purpose, an apparatus is proposed for imaging and/or analyzing a sample with high resolution by means of electrically charged particles, in particular using an electron beam, the apparatus comprising: a device for providing electrically charged particles; a chamber comprising means for receiving and holding the sample; a device for guiding the electrically charged particles along a central axis MZ towards the chamber; and a detector. A sample arranged in the chamber can be subjected to the electrically charged particles during operation.Furthermore, a device is provided for compensating for a magnetic interference field and for establishing a preferably elongated compensation volume having its greatest extent along the central axis MZ, wherein an existing magnetic interference field can be reduced within the compensation volume during operation.