Stacked Micro LED Epitaxial Structure for Small-Pitch Efficiency
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Solution Overview
Problem
The light emission efficiency of micro LEDs degrades as their pitch and dimension become smaller, leading to suboptimal performance in applications such as self-emissive micro-displays and visible light communications.
Innovation Solution
A micro LED structure is proposed, featuring multiple light emitting layers, including a first and second P-type semiconductor layer, light emitting layers, and N-type semiconductor layers, which are electrically connected to electrodes, enhancing light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pitch and dimension of micro LED are reduced to achieve higher resolution, then the resolution is improved, but the light emission efficiency seriously degrades
Solution Approach 1:
The patent introduces multiple light emitting layers stacked vertically (first light emitting layer, second light emitting layer, third light emitting layer) to transform the single-plane light emission into a multi-dimensional structure. This vertical stacking allows light to be emitted from multiple heights, compensating for the reduced lateral dimensions and maintaining light emission efficiency despite smaller pitch and dimension.
Solution Approach 2:
The patent employs a composite semiconductor structure with multiple P-type layers, N-type layers, and light emitting layers formed through epitaxial growth. This composite material approach creates optimized optical and electrical properties that maintain high light emission efficiency even when the micro LED dimensions are reduced for higher resolution displays.
2Loss of energy
If multiple light emitting layers are added to improve light emission efficiency, then the light emission efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent divides the light emitting function into multiple independent light emitting layers, each capable of contributing to the overall light output. This segmentation allows each layer to be optimized independently while working together to achieve high light emission efficiency, managing complexity through functional decomposition.
Solution Approach 2:
The patent merges multiple light emitting layers into a single integrated micro LED structure through epitaxial growth, creating a unified device that functions as one cohesive unit. This combining approach maintains structural integrity and simplifies fabrication processes despite the increased number of functional layers.
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 multi-layered micro LED structure improves light emission efficiency by allowing for better strain relaxation, improved light extraction, and uniform current spreading, thereby addressing the efficiency degradation issues in smaller micro LEDs.
Implementation Method 1
a first light emitting layer formed on the first P type semiconductor layer; an N type semiconductor layer formed on the first light emitting layer; a second light emitting layer formed on the N type semiconductor layer
Data Source
AI summary
A micro LED includes a bonding layer provided at a bottom of the micro LED; a first P type semiconductor layer formed on the bonding layer and electrically connected to the bonding layer; a first light emitting layer formed on the first P type semiconductor layer; a N type semiconductor layer formed on the first light emitting layer; a second light emitting layer formed on the N type semiconductor layer; and a second P type semiconductor layer formed on the second light emitting layer; wherein the first P type semiconductor layer and the second P type semiconductor layer are electrically connected to a first electrode, and the N type semiconductor layer is electrically connected to a second electrode.