Emitter Mounting Bore With Colloidal Fixative for Precise Beam Alignment
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Solution Overview
Problem
Existing charged particle beam sources face challenges in precisely aligning and securely attaching emitter filaments made of low workfunction materials like lanthanum hexaboride or cerium hexaboride, due to difficulties in electrical spot welding and reliance on frictional engagement or complex methods like focused ion beam welding, which are time-consuming and costly.
Innovation Solution
A charged particle beam source configuration where the emitter member is retained within a bore of a mounting member using a fixative material layer formed from a colloidal liquid, such as graphite, eliminating the need for clamping and allowing for precise alignment and stable operation at elevated temperatures without compressive force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If frictional engagement or compressive force clamping is used to attach the emitter filament, then the attachment method is simple, but the alignment precision is poor and time-consuming
Solution Approach 1:
The patent introduces a mounting member as an intermediary component between the emitter filament and the heating element structure. This mounting member provides precise alignment features and secure attachment mechanisms, eliminating the need for complex manual alignment while maintaining manufacturing simplicity. The mounting member acts as a mediator that combines the benefits of both simple attachment and high precision alignment.
2Strength
If focused ion beam welding is used to secure the filament, then the attachment strength is high, but the production time is long and cost is high
Solution Approach 1:
The patent segments the attachment function into two parts: mechanical alignment/retention through the mounting member structure, and electrical/thermal connection through contact surfaces. This segmentation eliminates the need for complex FIB welding while maintaining both attachment strength and production efficiency. The mounting member's structured design provides inherent mechanical retention without requiring additional welding steps.
Solution Approach 2:
The patent replaces the complex FIB welding process (a sophisticated mechanical/physical process requiring vacuum and specialized equipment) with a simpler mechanical retention system using the mounting member. This substitution maintains attachment strength while dramatically improving productivity by eliminating the need for vacuum-based welding processes.
3Reliability
If Vogel mount with high electrical heating currents is used, then the emitter cleaning is effective, but the thermal stability is poor
Solution Approach 1:
The patent applies local quality by providing optimized thermal contact surfaces specifically at the interface between the mounting member and the emitter filament. This localized thermal management ensures effective heat transfer for emitter cleaning while maintaining overall thermal stability through the mounting member's thermal mass and conductive pathways designed for uniform heat distribution.
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 enables smaller, more precise, and cost-effective charged particle beam sources with improved thermal stability and reduced production time, as the emitter member can be automatically aligned and secured without the need for vacuum conditions, enhancing productivity and reliability.
Implementation Method 1
the emitter member is retained by a fixative material layer formed from a colloidal liquid
Implementation Method 2
when electrically biased and/or thermally heated (e.g., for Schottky emitters), emits a beam of charged particles
Data Source
Figure 1
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Figure 4~5
AI summary
A charged particle beam source, such as for use in an electron microscope, can include an electrically conductive support member coupled to a base, a mounting member coupled to the support member and defining a bore, and an emitter member received in the bore and retained by a fixative material layer flowed around the emitter member in the bore.