Field Emitter X-Ray Tube Gate Layout for Short-Circuit Isolation
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Solution Overview
Problem
Existing X-ray tubes using field effect emitters face issues with excessive gate currents and short circuits due to manufacturing errors, mechanical damage, or flashovers, leading to non-uniform control and increased complexity and costs when subdividing gate and emitter electrodes into independent subregions.
Innovation Solution
The gate electrode is subdivided into a main region and additional regions by insulating structures, with connecting bridges, allowing automatic separation of malfunctioning regions through fusible cutouts in case of short circuits, eliminating the need for active deactivation and complex control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate electrode and emitter electrode are subdivided into independent subregions to maintain functionality after short circuits, then reliability is improved, but device complexity and control system requirements increase significantly
Solution Approach 1:
The gate electrode is subdivided into a first region and a second region separated by an insulating structure, allowing independent electrical control of each region. This segmentation enables the first region to continue functioning even if the second region experiences a short circuit, thereby maintaining overall device reliability while avoiding complex active control systems.
Solution Approach 2:
An insulating structure with a connecting bridge is introduced between the first and second regions of the gate electrode. This intermediary element provides a controlled electrical connection that can be opened in response to short circuits, automatically isolating the affected region without requiring complex sensor systems or active control logic.
2Device complexity
If uniform control of gate electrode and emitter electrode is used without subdivision, then device complexity is reduced, but the entire array fails when a short circuit occurs
Solution Approach 1:
The gate electrode is divided into independently controllable regions (first region and second region) separated by an insulating structure. This segmentation allows the unaffected first region to continue operating even when the second region experiences a short circuit, preventing total array failure while maintaining relatively simple control architecture.
Solution Approach 2:
Different regions of the gate electrode are given different electrical characteristics through the insulating structure and connecting bridge arrangement. The first region can maintain its electrical properties independently of the second region, allowing localized failure containment while preserving overall device functionality.
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 enables automatic isolation of faulty regions, maintaining functionality of the X-ray tube by preventing excessive current flow and reducing complexity and costs, while allowing independent control of emitter needle groups.
Implementation Method 1
the gate electrode is subdivided into a main region and a number of additional regions by insulating structures introduced into the gate electrode
Implementation Method 2
allowing automatic separation of malfunctioning regions through fusible cutouts in case of short circuits
Implementation Method 3
Silicon Field Emitter Arrays With Current Densities Exceeding 100 A/cm2 at Gate Voltages Below 75 V
Implementation Method 4
via which gate electrodes the electrical field is formed which excites the electrons to leave the emitter needles
Data Source
AI summary
An X-ray tube has a tube body, which encloses a tube volume in a gas-tight manner. An emitter electrode, a gate electrode and an anode are arranged within the tube volume. The emitter electrode is embodied as an unheated electrode which has a plurality of emitter needles arranged on a substrate in a region facing the gate electrode. The gate electrode is divided into a main region and a number of additional regions by insulating structures introduced into the gate electrode. An emission voltage is applied to the main region relative to the emitter electrode. The additional regions are electrically conductively connected to the main region only by way of connecting bridges. At least one cutout of the gate electrode is arranged in the additional regions in each case.