Nanostructured Semiconductor Anode for Field Emission Lighting
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Solution Overview
Problem
Current lighting technologies, such as incandescent bulbs and traditional LEDs, are inefficient and pose environmental and health risks, while solid-state lighting solutions struggle to match the voltage and current requirements of standard power grids and provide limited color options and spectral quality.
Innovation Solution
The development of lighting devices that inject electrons from a field emission cathode into nanostructured semiconductor materials, enabling highly efficient electroluminescent emission and using nanostructured semiconductor materials as phosphors for conventional LEDs and CFLs, allowing for high efficiency, rich color options, and compatibility with standard power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional LED structures are used, then device complexity is reduced, but efficiency and color quality are insufficient
Solution Approach 1:
The device is divided into functionally independent components: a field emission cathode separate from the semiconductor anode, allowing electrons to be emitted and accelerated independently before interacting with the nanostructured semiconductor material. This segmentation enables high efficiency electron-hole recombination while maintaining manageable device complexity through modular architecture.
Solution Approach 2:
The invention employs composite nanostructured semiconductor materials combining different semiconductor compounds (e.g., CdSe, ZnS, InP) with distinct bandgaps to achieve multiple emission wavelengths simultaneously. This composite approach enables rich color output and high efficiency without requiring multiple separate LED chips, thus improving energy efficiency while controlling device complexity.
2Illumination intensity
If multiple LEDs of different colors are used to produce white light, then color quality improves, but device complexity increases
Solution Approach 1:
A single semiconductor anode structure is designed to perform multiple functions by incorporating nanostructures of different materials (CdSe for red, InP for green, ZnS for blue) that emit different wavelengths. This multi-functional anode replaces the need for multiple separate LED chips, achieving full-color capability while simplifying the overall device architecture.
Solution Approach 2:
Multiple wavelength-emitting nanostructures are merged into a unified semiconductor anode assembly that receives electrons from a common cathode. The different nanostructured materials are spatially arranged within the same anode structure, combining their light emission functions into a single integrated component that produces rich color or white light.
3Ease of manufacture
If conventional phosphors are used in LEDs, then manufacturing is simplified, but efficiency is limited due to charge dissipation requirements
Solution Approach 1:
The invention changes the fundamental operating parameter from photoluminescence (phosphor absorption and re-emission) to direct electroluminescence (electron-hole recombination in semiconductor nanostructures). This parameter change eliminates the inefficiency of charge dissipation in conventional phosphors while maintaining ease of manufacture through established semiconductor fabrication techniques.
Solution Approach 2:
The patent replaces the passive phosphor conversion mechanism with an active electroluminescent emission mechanism. Instead of using phosphors that require photon absorption and subsequent emission (a two-step process with inherent losses), the system uses semiconductor nanostructures that directly convert electrical energy to light through electron-hole recombination, achieving higher efficiency while remaining manufacturable.
4Ease of manufacture
If blue LEDs with yellow phosphors are used, then manufacturing is simplified, but color tunability is lost
Solution Approach 1:
Different regions of the semiconductor anode are assigned different nanostructured materials with specific bandgaps tailored to emit particular wavelengths. This local quality differentiation within the anode structure enables independent control of color emission from different areas, providing color tunability while using standardized manufacturing processes for each material region.
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
These devices achieve high efficiency, low energy consumption, rich color options, and environmental sustainability, with estimated efficiencies exceeding 90% and long operational life, while being mercury-free and compatible with traditional power grids.
Implementation Method 1
injecting electrons from field emission cathode across a gap into nanostructured semiconductor materials
Implementation Method 2
electrons undergo electron-hole (e-h) recombination resulting in a highly efficient electroluminescent (EL) emission
Data Source
AI summary
Embodiments of the invention include methods and devices for producing light by injecting electrons from field emission cathode across a gap into nanostructured semiconductor materials, electrons issue from a separate field emitter cathode and are accelerated by a voltage across a gap towards the surface of the nanostructured material that forms part of the anode. At the nanostructure material, the electrons undergo electron-hole (e-h) recombination resulting in electroluminescent (EL) emission. In a preferred embodiment lighting device, a vacuum enclosure houses a field emitter cathode. The vacuum enclosure also houses an anode that is separated by a gap from said cathode and disposed to receive electrons emitted from the cathode. The anode includes semiconductor light emitting nano structures that accept injection of electrons from the cathode and generate photons in response to the injection of electrons. External electrode contacts permit application of a voltage differential across the anode and cathode to stimulate electron emissions from the cathode and resultant photon emissions from the semiconductor light emitting nanostructures of the anode. Embodiments of the invention also include the usage of nanostructured semiconductor materials as phosphors for conventional planar LED and nanowire array light emitting diodes and CFL. For the use in conventional planar LEDs, the nanostructures may take the form of quantum dots, nanotubes, branched tree-like nanostructure, nanoflower, tetrapods, tripods, axial heterostructures nanowires hetero structures.