Field Emission Cathode with Nanostructured Segments
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing field emission lighting technologies, such as fluorescent lamps, contain hazardous mercury and have complex recycling issues, and there is a need for more efficient and environmentally friendly alternatives that can improve luminous efficiency and lifespan.
Innovation Solution
A field emission cathode design featuring spatially distributed micrometer-sized sections with interconnected nanostructures, preferably ZnO nanostructures, which enhance electron emission and reduce power consumption, integrated into a field emission arrangement with a conductive base structure and an anode structure within an evacuated envelope.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional fluorescent light sources are used, then light emission is achieved, but hazardous mercury is contained and complex recycling issues arise
Solution Approach 1:
The invention changes the fundamental emission mechanism from fluorescent (mercury-based UV excitation) to field emission (electron emission via quantum tunneling under high electric field). This parameter change in the emission physics eliminates mercury while achieving efficient light generation through phosphor excitation by field-emitted electrons.
Solution Approach 2:
The invention replaces the thermal-mechanical heating process of traditional incandescent and fluorescent lamps with a cold cathode field emission process. Electrons are emitted via quantum tunneling under high electric field without thermal heating, eliminating mercury and reducing energy consumption while maintaining lighting efficiency.
2Reliability
If conventional cathode designs are used, then device simplicity is maintained, but electron emission efficiency is insufficient
Solution Approach 1:
The cathode is segmented into micrometer-sized sections distributed across the cathode structure. Each section contains multiple nanoscale protrusions that act as individual emission sites. This segmentation increases the total emission surface area and provides numerous electron emission pathways, significantly improving emission efficiency.
Solution Approach 2:
The invention transitions from planar cathode surfaces to three-dimensional nanoscale protrusions with high aspect ratios. The vertical dimension of sharp nanoscale tips creates intense local electric fields that enhance electron emission via field emission, while the distributed micrometer-sized sections provide spatial coverage across the cathode surface.
3Illumination intensity
If high voltage (4-12 kV) is applied to achieve high light emission, then luminous output is improved, but power consumption increases
Solution Approach 1:
The cathode structure creates highly localized intense electric fields at the sharp nanoscale tips of each protrusion. This local field enhancement allows efficient electron emission at lower overall voltages compared to conventional uniform field cathodes. The micrometer-sized sections distribute these localized high-field regions across the cathode surface, improving light output while reducing total power consumption.
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 design improves electron emission and light output while reducing power consumption, enabling more efficient and environmentally friendly field emission lighting and display applications.
Implementation Method 1
The electron emission is caused by a voltage between the anode and the cathode. For achieving high emission of light it is desirable to apply the voltage in a range of 4 -12 kV.
Implementation Method 2
The anode consists of a transparent electrically conductive layer and a layer of phosphors coated on the inner surface of a cylindrical glass tube. The phosphors are luminescent when excited by electrons.
Data Source
Figure 1~2c
Figure 3a~3b
Figure 4
AI summary
The present invention relates to a field emission cathode, comprising an at least partly electrically conductive base structure, and a plurality of electrically conductive micrometer sized sections spatially distributed at the base structure, wherein at least a portion of the plurality of micrometer sized sections each are provided with a plurality of electrically conductive nanostructures. Advantages of the invention include lower power consumption as well as an increase in light output of e.g. a field emission lighting arrangement comprising the field emission cathode.