Emitter Mounting Structure for Precise Charged Particle Beam Alignment
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Solution Overview
Problem
Existing charged particle beam sources face challenges in precisely aligning emitter filaments due to difficulties in attachment methods like frictional engagement or FIB welding, which are time-consuming and costly, and require high electrical heating currents, leading to thermal instability.
Innovation Solution
A charged particle beam source with a mounting member and fixative material layer that secures the emitter member in a bore without clamping, using a fixative material like colloidal graphite applied through channels in the mounting member, allowing precise alignment and stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If frictional engagement or compressive force methods are used to retain the emitter filament, then the emitter can be retained without spot welding, but precise alignment becomes difficult and time consuming
Solution Approach 1:
A fixative material layer is introduced as an intermediary substance between the emitter filament and the mounting member. This layer flows around the emitter in a bore to secure it in place, enabling both easy attachment and precise alignment simultaneously. The fixative material acts as a mediator that bonds the emitter to the mounting structure without requiring complex mechanical retention or spot welding.
2Manufacturing precision
If FIB welding is used to secure the filament, then precise alignment can be achieved, but the process becomes time consuming, technically complex, and costly
Solution Approach 1:
The complex FIB welding process is replaced with a simpler chemical/physical bonding method using a fixative material layer. Instead of using focused ion beams to weld the emitter to the mounting member, the patent employs a flowable fixative material that can be applied more easily and cures to secure the emitter in precise alignment, significantly reducing production time and technical complexity.
3Ease of manufacture
If Vogel mounts are used to clamp the filament, then the emitter can be retained, but relatively high electrical heating currents are required which introduce thermal stability problems
Solution Approach 1:
The problematic clamping mechanism of traditional Vogel mounts is extracted and replaced. Instead of using mechanical clamps that require high heating currents to function properly, the patent employs a fixative material layer that chemically or physically bonds the emitter to the mounting member. This eliminates the need for high clamping forces and associated high heating currents, thereby improving thermal stability.
4Strength
If spot welding is used to attach the emitter, then strong mechanical attachment is achieved, but low workfunction compound materials cannot be attached by this method
Solution Approach 1:
The attachment method is changed from mechanical spot welding to chemical/physical bonding using a fixative material layer. This parameter change in the attachment mechanism allows compatibility with low workfunction compound materials (such as lanthanum hexaboride or cerium hexaboride) that cannot be spot welded, while still achieving strong mechanical attachment through the cured fixative material.
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
Facilitates precise alignment and stable operation of emitter filaments, reducing production time and cost while improving thermal stability and alignment with the optical axis, enabling smaller and more efficient beam sources.
Implementation Method 1
the fixative material layer is formed from a dispersed phase of a colloidal liquid
Data Source
AI summary
A charged particle beam source, such as for use in an electron microscope, can include a mounting member defining a first opening at a free end of the mounting member and a bore extending from the first opening into the mounting member along a longitudinal axis of the mounting member. A second opening can be defined in a side wall of the mounting member and can extend between an outer surface of the mounting member and the bore, the second opening being spaced apart from the first opening along the longitudinal axis of the mounting member. An emitter member can be received in the bore and aligned along the longitudinal axis of the mounting member. A fixative material can be received in the bore and in the second opening to retain the emitter member in the bore.