Electron Gun Intermediate Electrode Drift Space Focal Adjustment
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Solution Overview
Problem
Existing methods for adjusting the focal position of an electron beam, such as using a Wehnelt electrode, can only adjust the focal point towards a shorter focal point and have a narrow range of adjustment, limiting the flexibility in adjusting the focal position in both directions after the electron gun is fitted on a counterpart device.
Innovation Solution
An electron gun design that includes an intermediate electrode with a drift space in the electron-beam passage hole, allowing the electron beam to expand, combined with a power source to apply voltages that disregard the electrical field effect, enabling adjustment of the focal position towards both shorter and longer focal points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a Wehnelt electrode is used to adjust the focal position, then the focal point can be adjusted toward a shorter focal point, but the adjustment range is narrow and the focal point cannot be adjusted toward a longer focal point
Solution Approach 1:
The invention divides the single Wehnelt electrode into two separate electrodes: a first Wehnelt electrode for adjusting the focal point toward a shorter focal point, and a second Wehnelt electrode for adjusting the focal point toward a longer focal point. This segmentation allows independent control of focal position in both directions, resolving the limitation of narrow adjustment range and inability to adjust toward longer focal points.
Solution Approach 2:
The invention introduces an intermediate electrode positioned between the photocathode and the anode, which acts as a mediator to create a drift space. This drift space allows electron beams to propagate without strong electrical field influence, enabling the second Wehnelt electrode to effectively adjust the focal point toward a longer focal point by controlling the electron beam width at the intermediate electrode, thereby expanding the adjustment range.
2Manufacturing precision
If a Wehnelt electrode is used to reduce beam size, then the focal position can be adjusted toward a shorter focal point, but the electron beam width can only be adjusted while passing through the electrode, limiting the adjustment range
Solution Approach 1:
The invention segments the focal adjustment function into two independent systems: one using the first Wehnelt electrode for precise focal adjustment toward shorter focal points, and another using the second Wehnelt electrode combined with the drift space for focal adjustment toward longer focal points. This segmentation enables both high precision and wide adjustment range simultaneously.
Solution Approach 2:
The invention adds a spatial dimension by introducing a drift space where electron beams propagate without strong electrical field influence. This creates a new dimension for controlling electron beam width, allowing the second Wehnelt electrode to adjust the focal point toward a longer focal point by controlling the beam width at the intermediate electrode, thereby expanding the adjustment range beyond the limitations of a single electrode system.
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
The design allows for flexible adjustment of the focal position in both directions, overcoming the limitations of traditional methods by providing a wider range of adjustment and improved control over the electron beam's focal point.
Implementation Method 1
a photocathode (3), and an anode (4)... an electron beam released from the photocathode (3) passes
Implementation Method 2
the electron-beam passage hole having formed therein a drift space in which, when an electrical field is formed between the photocathode and the anode due to application of a voltage, the effect of the electrical field can be disregarded
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
The present invention addresses the problem of providing a device with which it is possible to adjust the focal point of an electron beam both toward a shorter focal point and toward a longer focal point after an electronic gun was fitted on a counterpart device. The aforementioned problem can be solved by an electron gun including a photocathode, and an anode, the electron gun furthermore comprising an intermediate electrode disposed between the photocathode and the anode, the intermediate electrode comprising an electron-beam passage hole through which an electron beam released from the photocathode passes, and the electron-beam passage hole having formed therein a drift space in which, when an electrical field is formed between the photocathode and the anode due to application of a voltage, the effect of the electrical field can be disregarded.