Core-Shell Light-Emitting Rod Electrodes for Better Light Extraction
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Solution Overview
Problem
The commercialization of rod light-emitting devices is hindered by difficulties in manufacturing electrode structures for current application and transferring them to a driving circuit layer, resulting in low light extraction efficiency compared to thin-film devices.
Innovation Solution
A light-emitting device with a core-shell structure, comprising a first semiconductor layer, an active layer, and a second semiconductor layer, is designed with a transparent electrode and a reflective electrode, where the reflective electrode is thicker than the transparent electrode, and an insulating layer is used to separate the rods, allowing for improved current spreading and light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rod light-emitting devices are used to achieve higher light extraction efficiency, then light extraction efficiency is improved, but manufacturing complexity and difficulty of integration increase
Solution Approach 1:
The device is segmented into multiple rod-shaped light-emitting elements arranged in an array, with each rod having a core-shell structure. This segmentation allows for standardized manufacturing of individual rods while achieving high light extraction efficiency through their geometric shape, and facilitates modular integration into display panels.
Solution Approach 2:
The electrode structure is designed with a common transparent electrode that serves multiple functions: it acts as a current injection electrode for all light-emitting rods, provides mechanical support for the entire array, and maintains electrical connection across multiple rods simultaneously. This universal electrode design simplifies manufacturing by eliminating the need for individual electrodes for each rod.
2Loss of energy
If rod light-emitting devices are used to achieve higher light extraction efficiency, then light extraction efficiency is improved, but ease of manufacture deteriorates
Solution Approach 1:
Multiple light-emitting rods are merged into a single integrated structure sharing common electrodes and encapsulation. The rods are arranged in close proximity with shared transparent and reflective electrodes, reducing the total number of manufacturing steps compared to producing and assembling individual LED devices. This merging approach maintains high light extraction efficiency while significantly improving ease of manufacture.
Solution Approach 2:
The light-emitting rods are nested within a common encapsulation structure that provides protective coating and structural support for the entire array. This nested design allows for simplified manufacturing where the encapsulation is formed as a single piece encompassing multiple rods, rather than requiring individual encapsulation for each rod.
3Reliability
If thicker reflective electrode is used to improve current spreading, then electrical conductivity is improved, but material consumption increases
Solution Approach 1:
The reflective electrode is designed with non-uniform thickness distribution, being thicker in regions requiring superior current spreading and electrical connection, and thinner in regions where less current flow is expected. This local variation in electrode quality optimizes current distribution while minimizing overall material consumption, achieving reliable electrical performance without excessive material use.
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 enhances light extraction efficiency and facilitates easier integration into display apparatuses by improving the contact area between the semiconductor layers and electrodes, enabling more efficient light emission and manufacturing processes.
Implementation Method 1
an active layer having a shell shape disposed about a plurality of surfaces of the first semiconductor layer
Implementation Method 2
a reflective electrode electrically connected to the second semiconductor layer of each of the plurality of light-emitting rods
Data Source
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AI summary
A light-emitting device may include a plurality of light-emitting rods. Each of the plurality of light-emitting rods may include a first semiconductor layer having a rod shape, an active layer having a shell shape disposed about a plurality of surfaces of the first semiconductor layer, and a second semiconductor layer having a shell shape disposed about a plurality of surfaces of the active layer. The light emitting device may further include an insulating layer disposed in spaces between the plurality of light-emitting rods; a transparent electrode electrically connected to the first semiconductor layer of each of the plurality of light-emitting rods; and a reflective electrode electrically connected to the second semiconductor layer of each of the plurality of light-emitting rods.