Virtual Matrix Control for Field Emitter Arrays
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Solution Overview
Problem
Field emitter arrays in x-ray tubes face challenges due to the large number of activation lines and vacuum feedthroughs, which lead to gas leaks and performance inhibition, and require a system that can address individual emitters independently of their physical topology.
Innovation Solution
A virtual matrix arrangement and addressing scheme that minimizes the number of voltage control channels needed to activate individual field emitter units, allowing for independent control of emitter elements and extraction grids, with the number of control channels determined by a pair of integers whose product equals the number of emitter elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If each field emitter is addressed via an associated bias or activation line, then individual emitter control is achieved, but the number of activation lines and vacuum feedthroughs increases significantly
Solution Approach 1:
The patent segments the control system into two independent parts: a common gate electrode that controls all emitters simultaneously, and individual bias lines that provide emitter-specific voltages. This segmentation allows individual emitter control while reducing the number of feedthroughs needed, as the gate control is shared across all emitters.
Solution Approach 2:
The common gate electrode serves as a universal control element for all field emitters in the array. By using a single gate electrode that can be controlled through one feedthrough, the system achieves multi-functionality where one component performs the control function for multiple emitters, significantly reducing the total number of feedthroughs required.
2Ease of operation
If a large number of vacuum feedthroughs are used to supply activation lines, then individual emitter addressing is enabled, but gas leaks occur that inhibit emitter performance
Solution Approach 1:
The control architecture is segmented into common gate control (requiring minimal feedthroughs) and individual bias control (using fewer feedthroughs than traditional approaches). This segmentation reduces the total number of vacuum feedthroughs, thereby maintaining vacuum integrity while still enabling individual emitter addressing through the bias lines.
Solution Approach 2:
The patent introduces bias lines as intermediary elements that carry individual emitter control voltages without requiring separate gate control feedthroughs for each emitter. These bias lines act as mediators that enable individual emitter control while minimizing the number of vacuum feedthroughs, thus preserving vacuum integrity.
3Adaptability or versatility
If field emitters are arranged in non-matrix patterns, then application-specific optimization is achieved, but connection to activation lines becomes more challenging
Solution Approach 1:
The common gate electrode serves as a universal control element that works regardless of the emitter arrangement pattern. Whether emitters are arranged in matrix, linear, or arbitrary patterns, the same gate control mechanism applies to all emitters simultaneously, simplifying the connection architecture and reducing complexity despite arrangement flexibility.
Solution Approach 2:
The patent separates the control dimensions into a shared dimension (gate control affecting all emitters) and individual dimensions (bias lines for each emitter). This dimensional separation allows emitters to be arranged in any spatial pattern while maintaining simplified control connections, as the gate control operates in a different dimension than the spatial arrangement.
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 approach reduces the number of activation lines and feedthroughs, enhances high voltage stability, and improves image quality by allowing for efficient electron beam focusing and reduced off-focal radiation, while maintaining flexibility in emitter array topology.
Implementation Method 1
Electron emissions in field-type electron emitter arrays are produced according to the Fowler-Nordheim theory relating the field emission current density of a clean metal surface to the electric field at the surface
Implementation Method 2
a protection and focusing scheme that functions to minimize degradation of the electron beam and allow for focusing of the electron beam into a desired spot size
Data Source
AI summary
A system and method for addressing individual electron emitters in an emitter array is disclosed. The system includes an emitter array comprising a plurality of emitter elements arranged in a non-rectangular layout and configured to generate at least one electron beam and a plurality of extraction grids positioned adjacent to the emitter array, each extraction grid being associated with at least one emitter element to extract the at least one electron beam therefrom. The field emitter array system also includes a plurality of voltage control channels connected to the plurality of emitter elements and the plurality of extraction grids such that each of the emitter elements and each of the extraction grids is individually addressable. In the field emitter array system, the number of voltage control channels is equal to the sum of a pair of integers closest in value whose product equals the number of emitter elements.