Electron Gun Cathode Assembly With Thermal Barrier Connection
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Solution Overview
Problem
Existing cathode assemblies in electron guns face challenges with expensive materials, poor beam quality due to aberrations, and contamination risks, along with difficulties in achieving a reliable thermal barrier between the emitting member and the carrier.
Innovation Solution
A cathode assembly design featuring a thermal barrier between the carrier and holder, with a smaller contact area and specific geometries like ridges and grooves, to reduce heat transfer and prevent contamination, using materials with lower work functions and separate heating sources for the emitting member and carrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the contact area between carrier and holder is reduced to minimize heat loss, then thermal energy transfer is reduced, but the mechanical strength and reliability of the connection deteriorate
Solution Approach 1:
The patent introduces a thermal barrier layer as an intermediary substance between the carrier and holder. This layer has low thermal conductivity to reduce heat transfer while maintaining adequate contact area for mechanical strength. The thermal barrier acts as a mediator that decouples the thermal and mechanical functions, allowing small contact areas to provide sufficient mechanical support without excessive heat conduction.
2Manufacturing precision
If expensive materials like LaB6 are used for the emitting member, then beam quality and brightness are improved, but manufacturing cost increases
Solution Approach 1:
The patent applies local quality by using expensive emitting materials like LaB6 only in the specific region where electron emission is required (the emitting surface), while the carrier and holder are made from cheaper materials. This localized application of high-performance materials optimizes beam quality at the emission point without unnecessarily increasing the cost of structural components that do not require such material properties.
3Productivity
If the emitting member is heated to high temperatures for electron emission, then electron beam generation is improved, but thermal distortion and contamination risk increase
Solution Approach 1:
The patent extracts the thermal management function from the emitting member by introducing a separate thermal barrier between the carrier and holder. This allows the emitting member to be heated to high temperatures for electron emission while the thermal barrier prevents excessive heat from transferring to the carrier and holder, thereby reducing thermal distortion and contamination risk in the surrounding structure.
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 reduces heat loss and energy requirements, improves beam quality, and allows for the use of cheaper materials, while minimizing thermal distortion and contamination risks, enhancing the stability and efficiency of electron guns in applications like 3D printing and electron microscopes.
Implementation Method 1
the emitting member emits charged particles from an emitting surface at an emitting temperature
Implementation Method 2
the cathode is heated by irradiation of the emitting member and/or the carrier from an external source
Implementation Method 3
the connection between said carrier and said holder provides a thermal barrier for reducing the amount of thermal energy transferred from the cathode to the holder
Data Source
AI summary
A cathode assembly for emitting charged particles, used in for example an electron gun as source for generating an electron beam. The cathode assembly has a cathode comprising an emitting member and a carrier. The emitting member is mounted in the carrier, and the carrier is electrically connected to a holder. The cathode is heated by irradiation from an external source, whereby the emitting member emits charged particles from an emitting surface at an emitting temperature. The connection between the carrier and the holder provides a thermal barrier for reducing the amount of thermal energy transferred from the cathode to the holder.