Spherical Aberration Correction via Aperture Plates
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Solution Overview
Problem
Existing spherical aberration correctors for charged particle beams are complex, large, expensive, and difficult to produce due to the need for precise alignment and potential difference application between electrodes, making them unsuitable for widespread use in electron microscopes.
Innovation Solution
A spherical aberration corrector that uses a combination of circular and ring-shaped apertures with no potential difference between the inner and outer portions of the ring-shaped aperture, allowing for a simpler structure and production process, where the potential difference is applied between the plates, enabling effective aberration correction without the need for precise coaxial insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spherical aberration corrector uses a circular column-shaped electrode inserted into a circular aperture electrode with potential difference applied, then spherical aberration can be corrected, but the structure becomes complicated and difficult to produce due to the need for precise coaxial alignment and insulation
Solution Approach 1:
The invention extracts the essential function of spherical aberration correction from the complex dual-electrode structure. By using a single plate electrode with a ring-shaped aperture instead of the conventional circular column-shaped electrode inserted into a circular aperture electrode, the patent removes the insulation and coaxial alignment requirements while maintaining the ability to generate the necessary electric field for aberration correction.
Solution Approach 2:
The invention changes the geometric parameters of the aperture from a circular column shape to a ring-shaped aperture in a single plate. This parameter change simplifies the structure by eliminating the need for nested electrodes and insulation, while the ring-shaped aperture still generates the required electric field distribution for correcting spherical aberration when potential difference is applied between the plate electrode and another electrode.
2Measurement precision
If precise coaxial alignment and insulation between inner and outer electrodes are required, then spherical aberration correction can be achieved, but production cost and difficulty increase significantly
Solution Approach 1:
The invention merges the functions of the inner electrode and outer electrode into a single plate electrode with a ring-shaped aperture. This consolidation eliminates the need for precise coaxial alignment and insulation between separate electrodes, significantly easing manufacturing while maintaining the ability to achieve precise aberration correction through potential difference application between the plate electrode and another electrode.
3Reliability
If conventional spherical aberration correctors are designed with multiple electrodes and insulation structures, then aberration correction is effective, but the device size becomes large and cost becomes expensive
Solution Approach 1:
The invention extracts and removes the unnecessary insulation structures and multiple electrode components from the conventional design. By using a single plate electrode with a ring-shaped aperture, the patent reduces device size and weight while maintaining effective spherical aberration correction functionality.
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 corrector effectively corrects spherical aberration in charged particle beams by generating a negative aberration that counteracts positive aberration from electromagnetic lenses, improving resolution and reducing production costs and complexity.
Implementation Method 1
a corrector that comprises: an incident plate arranged on an incident side of a charged particle beam; and an emission plate arranged on an emission side of the charged particle beam
Data Source
Figure 1~2
Figure 3(1)~3(4)
Figure 4~5
AI summary
Technical Problem: An electromagnetic lens for charged particle beam exhibits positive spherical aberration. A complicated combination of electromagnetic lenses had been necessary for correcting this spherical aberration. Solution: One of a circular aperture or a ring-shaped aperture is provided on an incident plate arranged on an incident side of charged particle beam, another of the circular aperture or the ring-shaped aperture is provided on a plate arranged on an emission side thereof, and a voltage is applied between the incident plate and the emission plate. By so doing, an electric field generated in the ring-shaped aperture emanates, which resolves the positive spherical aberration. The spherical aberration can be corrected by an extremely simple and easily implemented structure.