Field Emission Electron Source Array with Insulating Layer and Conductive Rings
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Solution Overview
Problem
Carbon nanotubes in field emission electron sources fabricated by the CVD method are prone to being pulled out by strong electric fields, leading to a short lifespan of the devices.
Innovation Solution
A method involving the creation of a freestanding linear carbon nanotube structure coated with an insulating layer and conductive rings, which is then cut to form field emission electron sources, ensuring secure attachment and stability under electric fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If carbon nanotubes are deposited on the exposed cathode electrode using CVD method, then the field emission electron source can be formed, but the carbon nanotubes are prone to be pulled out by strong electric field force resulting in short lifespan
Solution Approach 1:
The patent segments the carbon nanotube structure by forming an insulating layer that divides the cathode electrode into multiple isolated regions. Each region contains carbon nanotubes that are electrically isolated from others, preventing collective pull-out failures and improving overall device lifespan while maintaining ease of manufacture through a systematic segmentation approach
Solution Approach 2:
The patent introduces an insulating layer as an intermediary between the cathode electrode and the carbon nanotubes. This intermediary layer provides mechanical support and electrical isolation, preventing the carbon nanotubes from being directly pulled out by electric field force while still allowing field emission to occur, thus resolving the contradiction between ease of manufacture and device lifespan
2Device complexity
If carbon nanotubes are directly deposited on cathode electrode, then the structure is simple and easy to manufacture, but the carbon nanotubes lack secure attachment and are easily pulled out
Solution Approach 1:
The patent applies preliminary action by forming the insulating layer on the cathode electrode before depositing the carbon nanotubes. This pre-prepared insulating structure provides immediate mechanical support and secure attachment points for the carbon nanotubes, eliminating the need for complex post-deposition reinforcement while maintaining simple manufacturing流程和enhancing attachment strength
3Reliability
If an insulating layer is formed on the cathode electrode before depositing carbon nanotubes, then the carbon nanotubes are securely attached and resistant to electric field pull-out, but the manufacturing process becomes more complex
Solution Approach 1:
The insulating layer serves multiple functions simultaneously: it provides electrical isolation between cathode regions, offers mechanical support to prevent carbon nanotube pull-out, and acts as a foundation for carbon nanotube deposition. This multi-functionality resolves the contradiction by achieving enhanced reliability through a single added layer rather than multiple complex components
Solution Approach 2:
The patent changes the physical and chemical parameters of the cathode electrode surface by coating it with an insulating layer. This parameter change transforms the surface properties to provide better mechanical adhesion and electrical isolation, securing the carbon nanotubes against electric field pull-out while maintaining a relatively simple manufacturing process
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 method enhances the mechanical strength and stability of carbon nanotube structures, preventing them from being pulled out by electric fields, thereby prolonging the lifespan of field emission electron sources and allowing for easier assembly and integration.
Implementation Method 1
coating an insulating layer on outer surface of the linear carbon nanotube structure
Implementation Method 2
coating a first conductive ring on outer surface of the insulating layer
Data Source
AI summary
A method for making field emission electron source array includes following steps. An insulating layer is coated on outer surface of a linear carbon nanotube structure. A field emission electron source preform is formed by locating a plurality of conductive rings on outer surface of the insulating layer, wherein the plurality of conductive rings is space from each other, and each conductive ring comprises a first ring face and a second ring face opposite to the first ring face. A field emission electron source array preform is formed by aligning a plurality of field emission electron source performs side by side. The field emission electron source array preform is severed to form a plurality of field emission electron arrays by cutting the plurality of conductive rings.