Field Emission Device With Protruding Gate Electrodes
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Solution Overview
Problem
Field emission devices face challenges in achieving uniform electron beam emission and high voltage application due to arc discharge and non-uniformity issues in existing triode-type structures, which affect fluorescence efficiency and manufacturing complexity.
Innovation Solution
A field emission device with a gate substrate having electrically isolated gate electrodes, where the sum of gate insulator and gate electrode heights is greater than the opening diameter, allowing for adjustable electron beam trajectories and high voltage application, using carbon nanotubes or nanofibers as field emitters and applying sine wave voltage patterns to gate electrodes for improved emission uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional triode-type structure with thin insulators is used, then the device can be manufactured with simpler processes, but arc discharge occurs and high voltage cannot be applied to the anode electrode
Solution Approach 1:
The patent transitions from a planar gate electrode structure to a three-dimensional protruding gate electrode structure that extends toward the anode substrate. This dimensional change allows the gate electrode to effectively block electric field lines without requiring thicker insulators, thereby preventing arc discharge while maintaining manufacturing feasibility.
Solution Approach 2:
The protruding gate electrode acts as an intermediary element between the cathode substrate and anode substrate, intercepting and redirecting electric field lines before they can cause arc discharge. This mediator structure enables high voltage application by controlling the electric field distribution in the vacuum space.
2Adaptability or versatility
If the gate electrode does not entirely block the electric field from the anode electrode, then complete triode operation cannot be achieved, but applying high anode voltage is still difficult
Solution Approach 1:
By extending the gate electrode in the vertical dimension toward the anode substrate, the patent achieves complete electric field blocking capability. This three-dimensional structure ensures that electric field lines from the anode electrode are fully intercepted by the gate electrode, enabling complete triode operation where electron emission is controlled solely by gate voltage.
3Device complexity
If a diode-type structure is used, then the structure is simple and easy to manufacture, but arc discharge in free space degrades fluorescence efficiency and electron beam uniformity
Solution Approach 1:
The protruding gate electrode serves as a mediator that organizes and controls the electric field in the vacuum space between cathode and anode substrates. This intermediary structure guides electron beams from field emitters to collide uniformly with the fluorescent layer, achieving uniform emission while maintaining a relatively simple overall device 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
The solution enhances emission uniformity and efficiency by expanding the electron beam-scanned area, allowing for higher anode voltage application without arc discharge, resulting in improved phosphor layer illumination and reduced manufacturing complexity.
Implementation Method 1
the field emitter 160 (e.g., carbon nanotube; CNT), which is formed on the cathode electrode 150 on the cathode substrate 140, emits elections
Implementation Method 2
The electrons are induced and accelerated by a voltage applied to the anode electrode 120 on the anode substrate 110
Implementation Method 3
a field emission device emits light using cathodoluminescence in a fluorescent layer on an anode substrate by causing electrons emitted from a field emitter on a cathode substrate to collide with the fluorescent layer
Data Source
AI summary
Disclosed is a field emission device. The field emission device includes: an anode substrate including an anode electrode formed on a surface thereof and a fluorescent layer formed on the anode electrode; a cathode substrate disposed opposite to and spaced apart from the anode substrate, and including at least one cathode electrode formed toward the anode substrate and a field emitter formed on each cathode electrode; and a gate substrate having one surface in contact with the cathode substrate, wherein the gate substrate include gate insulators surrounding the field emitters and having a plurality of openings exposing the field emitters, and a plurality of gate electrodes formed on the gate insulators around the openings and electrically isolated from one another. Thus, when the trajectories of the electron beams emitted from the emitters are rapidly changed over time by a voltage difference between the gate electrodes, an electron beam-scanned area can be expanded due to residual images and the electron beam can be more uniformly emitted due to an electron beam scattering effect and a linear beam spreading effect, resulting in improved emission uniformity of the fluorescent layer.