Arch-Shaped Thermal Field Emitter for Electron Source Stability

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Solution Overview

Problem

Thermal field emission emitters face issues with electron source displacement due to thermal deformation of the filament, leading to deviations in electron beam irradiation direction and position.

Innovation Solution

The emitter design incorporates an arch-shaped filament with bent portions between the electron source and terminals, allowing for stress relaxation due to thermal deformation and minimizing electron source displacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the filament is heated to high temperature for electron emission, then electron emission characteristics are improved, but thermal deformation causes electron source displacement

Engineering Contradiction:

Improveelectron emission characteristicsVSAvoidelectron source position accuracy

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The filament is designed with a curved arch shape instead of a straight configuration. This curvature provides thermal expansion compensation, allowing the filament to deform under heat without causing significant displacement of the electron source relative to the electrodes, thus resolving the contradiction between high-temperature operation and position accuracy.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The filament geometry parameters (curvature radius, arch shape) are specifically optimized to compensate for thermal deformation. By changing the physical parameters of the filament structure, the system maintains electron source positioning accuracy even at high operating temperatures required for good electron emission.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If the filament is made rigid to maintain position, then position stability is improved, but thermal stress causes deformation and displacement

Engineering Contradiction:

Improveelectron source position stabilityVSAvoidfilament structural integrity

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The curved arch shape of the filament acts as a stress-absorbing structure that can flex under thermal load without breaking. This geometric design allows the filament to maintain both rigidity for position stability and flexibility for stress relief, preventing structural failure while maintaining positioning accuracy.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 design effectively reduces the deviation of electron beam irradiation direction and position, maintaining coaxiality and improving electron emission characteristics.

Implementation Method 1

Since a filament provided in a thermal field emission emitter is heated to approximately 1,800 K at the time of operation

Methodology Applied

Scientific EffectThermal heating: Heating

Implementation Method 2

A thermal field emission emitter is known as a form of an emitter

Methodology Applied

Scientific EffectThermal field emission: Thermionic Emission

Data Source

PatentEP4303906B1Emitter and device provided with same

Publication Date: 2025.01.29 DENKA CO LTD

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AI summary

An emitter includes an insulator, a pair of terminals attached to the insulator separately from each other, at least one filament attached between the pair of terminals in an arch shape, and an electron source fixed to the filament. The filament has bent portions between a contact with respect to the electron source and contacts with respect to the terminals. A device is provided with the emitter.