Electron Emission Cathode Structure for Stable Brightness Control
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Solution Overview
Problem
The existing cathode mechanisms in electron emission sources face a short operational life due to wear, leading to premature end of cathode life and frequent apparatus downtime, as the electron emission surface retreats and desired brightness distribution cannot be maintained.
Innovation Solution
A cathode mechanism featuring a crystal with a column or truncated cone shape, integrated with a holding part of varying diameters to project the electron emission surface accurately, and a retaining part to secure the crystal, ensuring the emission surface remains optimally positioned and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the crystal is used without side surface covering, then the apparatus operation time is extended, but the brightness distribution control becomes difficult
Solution Approach 1:
The crystal is divided into two functional parts: an upper part with side surface covering for controlled electron emission, and a lower part without covering for extended operational life. This segmentation allows different regions to serve different purposes, resolving the contradiction between brightness control and operation duration.
Solution Approach 2:
Different parts of the crystal have different surface properties: the upper part has covering material for precise brightness distribution control, while the lower part remains uncovered to extend cathode life. This local differentiation resolves the contradiction by applying quality control only where necessary.
2Duration of action of stationary object
If the electron emission surface retreats from the covering material edge, then the cathode life reaches the end, but the desired brightness distribution cannot be acquired
Solution Approach 1:
The holding part is designed with a columnar structure that preliminarily positions the crystal at the correct height, ensuring the electron emission surface maintains the proper distance from the covering material edge. This preliminary positioning prevents both premature cathode failure and brightness distribution degradation.
Solution Approach 2:
The holding part acts as an intermediary between the crystal and the apparatus, mechanically maintaining the crystal at the optimal position. This intermediary structure ensures the electron emission surface remains at the correct distance from the covering material edge throughout operation.
3Loss of time
If the crystal projection amount is not controlled accurately, then the apparatus downtime increases, but the operational efficiency is reduced
Solution Approach 1:
The holding part's columnar structure with specific inner diameter automatically maintains the crystal at the correct projection amount through mechanical constraint. This self-regulating design eliminates the need for frequent manual adjustments, reducing apparatus downtime while maintaining operational efficiency.
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 extends the cathode life by maintaining a desired brightness distribution and reducing downtime, allowing for more accurate control of the electron emission surface projection and enhancing the operational efficiency of electron beam writing apparatuses.
Implementation Method 1
a first surface to emit thermoelectrons by heating
Data Source
AI summary
A cathode mechanism of an electron emission source includes a crystal that includes an upper part being columnar, truncated conical, or their combined shape, and having a first surface to emit thermoelectrons, and a lower part, integrated with the upper part, having a second surface substantially parallel to the first surface, and a diameter larger than the maximum diameter of the upper part, a holding part that is a column having, in order from the holding part upper side, different inner diameters of a first diameter and a second diameter larger than the first one, and that holds the crystal in the state where the crystal first surface is projecting from the upper surface, and the crystal second surface contacts the holding part inside the column, and a retaining part that retains the crystal, at the back of the crystal lower part, not to be separated from the holding part.