Field Emission Device Shielding Barrel Stability
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Solution Overview
Problem
Conventional field emission devices using carbon nanotubes in tips are prone to instability due to high working voltages, leading to performance issues.
Innovation Solution
A field emission device design featuring a sealed container with light-permeable portions, phosphor layers, and a shielding barrel with a conductive nano-material layer on its inner surface, which enhances stability by distributing the electric field effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high working voltage (10,000 volts) is applied to generate sufficient electron emission, then brightness and performance are improved, but carbon nanotubes break due to static force, causing instability
Solution Approach 1:
The patent segments the cathode structure by introducing a shielding barrel with conductive nano-material coating inside the container. This creates separate electric field zones that distribute the high voltage stress, preventing concentration on single carbon nanotube tips and reducing breakage while maintaining brightness
Solution Approach 2:
The shielding barrel acts as an intermediary component between the high voltage source and the carbon nanotube cathode. It mediates the electric field distribution, allowing high voltage operation without direct exposure of carbon nanotubes to full voltage stress, thus preventing breakage while maintaining emission performance
2Weight of moving object
If carbon nanotubes are used in tips to enable field emission, then device weight is reduced and performance is improved, but the device becomes unstable due to voltage-induced breakage
Solution Approach 1:
The patent applies local quality by coating only the inner surface of the shielding barrel with conductive nano-materials. This localized modification creates specific electric field distribution zones where carbon nanotubes are protected from excessive voltage stress, maintaining both weight advantages and operational stability
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 allows for stable operation at higher voltages, improving the reliability and performance of field emission devices by reducing the risk of carbon nanotube breakage.
Implementation Method 1
A conductive nano material layer is formed on the inner surface of the shielding barrel... enhances stability by distributing the electric field effectively
Implementation Method 2
Electrons are emitted from micron-sized tips in a strong electric field, and the electrons are accelerated and collide with a fluorescent material. The fluorescent material then emits visible light
Data Source
AI summary
A field emission device (10) includes a sealed container (12) with a first light-permeable portion (120) and an opposite second light-permeable portion (122). A first phosphor layer (14) is formed on the first light-permeable portion. A first light-permeable anode (16) is formed on the first light-permeable portion. A second phosphor layer (18) is formed on the second light-permeable portion. A second light-permeable anode (20) is formed on the second light-permeable portion. A shielding barrel (22) is disposed within the container and electrically connected to at least one cathode electrode (25, 26). The shielding barrel has opposite open ends facing toward the first and the second light-permeable portions respectively. The shielding barrel has an inner surface, and a slurry layer (24) containing conductive nano material is formed on the inner surface of the shielding barrel.