Tube-Structured Micro LED for Illumination Efficiency
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Solution Overview
Problem
Vertically-structured micro LEDs face challenges in tuning colors and maintaining mono-chromaticity due to their complex geometric structure, which affects illumination efficiency.
Innovation Solution
A method of forming a micro LED involving the growth of hollow micrometer/nanometer tubes on a substrate, followed by the sequential deposition of n-GaN, multiple quantum well, and p-GaN layers, with electrodes formed on the outer and inner sides of the PN junction, creating a tube structure that reduces impedance and enhances conductivity and illumination efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a vertically-structured micro LED is used to provide larger illumination area and improve output coupling efficiency, then illumination efficiency is improved, but the complicated geometric structure makes it difficult to tune colors and maintain mono-chromaticity
Solution Approach 1:
The invention segments the micro LED structure into distinct functional regions: a vertically-structured active region for light emission and a horizontally-structured electrode region for current injection. This segmentation allows the active region to maintain vertical geometry for high illumination efficiency while the electrode structure provides horizontal current distribution for uniform color emission across the pixel area.
Solution Approach 2:
The invention transitions from a purely vertical or horizontal structure to a hybrid structure that utilizes both vertical and horizontal dimensions strategically. The active region employs vertical stacking for efficient light-coupling, while the electrode and pixel electrode extend horizontally to ensure uniform current distribution across the emission area, thereby maintaining mono-chromaticity.
2Power
If a vertically-structured micro LED is used to improve output coupling efficiency, then output coupling efficiency is improved, but the complicated geometric structure makes it difficult to tune colors
Solution Approach 1:
The micro LED is segmented into an active region with vertical structure for high power output coupling and a surrounding electrode region with horizontal structure for versatile color tuning. This allows independent optimization of each function: the vertical active region maximizes light extraction efficiency while the horizontal electrode structure enables uniform current injection for accurate color rendering and tuning.
Solution Approach 2:
The invention employs vertical dimension for power efficiency (active region) and horizontal dimension for color control (electrode structure). This multi-dimensional approach enables the device to achieve both high output coupling efficiency and superior color tuning capability by assigning different spatial orientations to different functional requirements.
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 tube-structured micro LED improves illumination efficiency and mono-chromaticity by lowering impedance and increasing current density, effectively addressing the color tuning and stability issues of vertically-structured micro LEDs.
Implementation Method 1
growing hollow micrometer/nanometer tubes on the pre-determined spots on the substrate to get a buffer layer column
Implementation Method 2
growing a n-GaN layer on the outer wall of the buffer layer column
Implementation Method 3
forming a multiple quantum well (MQW) layer and a p-GaN layer sequentially on the n-GaN layer
Implementation Method 4
The tube-structured micro LED improves illumination efficiency and mono-chromaticity by lowering impedance and increasing current density
Data Source
AI summary
The present disclosure proposes a micro LED and a method of forming the same. After a body of layers to structure a PN junction is formed sequentially on the outer wall of a buffer layer column, a first electrode is formed on the outer side of the body of layers that structured the PN junction. A second electrode is formed on the inner side of the body of layers that structured the PN junction after the buffer layer column is removed. The first electrode and second electrode are insulating to each other in areas outside of the body of layers structuring the PN junction. The micro LED formed is of a tube structure. The tube-structured micro LED can effectively lower the impedance imposed by the body of layers structuring the PN junction between the first and second electrodes, and thus enhance conductivity and illumination efficiency of the micro LED.