Micro LED Array with Continuous Active Layer and Light Outcoupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing mini/micro LED arrays face challenges with decreased internal quantum efficiency and light extraction as pixel sizes shrink, due to non-radiative recombination at etched sidewalls and inter-pixel light propagation issues, which affect contrast and overall light output.
Innovation Solution
A semiconductor light-emitting array design with a continuous active layer and outcoupling structures, where the first and second semiconductor layers and the junction are coextensive, and protruding portions of the second semiconductor layer collect and redirect light, forming discrete pixel regions without physical separation, enhancing internal quantum efficiency and light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pixel sizes are shrunk to form mini/micro LED arrays, then device density and integration are improved, but internal quantum efficiency and light extraction deteriorate due to non-radiative recombination at etched sidewalls
Solution Approach 1:
The patent divides the continuous active layer into discrete pixel regions through electrical segmentation using conductive layers and contacts, rather than physical segmentation via etching. This allows high device density while avoiding the creation of etched sidewalls that cause non-radiative recombination, thus maintaining internal quantum efficiency even as pixel sizes shrink to mini/micro dimensions.
Solution Approach 2:
The patent extracts or removes the harmful etched sidewalls from the pixel structure by using a planar continuous active layer definition approach. Instead of etching trenches to define pixels, the invention uses electrical isolation layers and conductive patterns to define pixel boundaries, eliminating the source of non-radiative recombination while preserving light extraction efficiency.
2Productivity
If pixel sizes are shrunk to form mini/micro LED arrays, then device density is improved, but light extraction and pixel contrast deteriorate due to inter-pixel light propagation
Solution Approach 1:
The patent applies local quality by positioning light management structures (such as reflective layers, scattering layers, or outcoupling structures) specifically within or adjacent to each discrete pixel region. This localized approach enhances light extraction for each pixel individually while maintaining high device density, and prevents inter-pixel light propagation by confining optical management to specific pixel areas.
Solution Approach 2:
The patent introduces intermediary light management layers or structures between the active layer and the packaging environment. These intermediaries (such as photonic crystals, scattering layers, or reflective layers) mediate the light extraction process, enhancing outcoupling efficiency while preventing light from propagating between adjacent pixels, thus maintaining pixel contrast at high device densities.
3Illumination intensity
If physical separation structures are added to prevent inter-pixel light propagation, then pixel contrast is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges the functions of pixel definition, electrical isolation, and light management into a unified structure. The conductive layers and isolation structures that define pixel regions also serve as the boundaries for light management, eliminating the need for separate physical separation structures. This integrated approach achieves high pixel contrast while minimizing device complexity and manufacturing difficulty.
Solution Approach 2:
The patent employs multi-functional layers and structures that simultaneously perform multiple roles: electrical isolation, pixel definition, and light management. For example, conductive isolation layers serve both to electrically separate pixels and to define pixel boundaries for optical confinement, reducing the overall structural complexity while maintaining high pixel contrast.
4Shape
If etched sidewalls are used to define pixel regions, then discrete pixel formation is achieved, but non-radiative recombination increases reducing internal quantum efficiency
Solution Approach 1:
The patent extracts or removes the harmful etched sidewalls from the pixel structure by using a planar continuous active layer definition approach. Instead of etching trenches to define pixels, the invention uses electrical isolation layers and conductive patterns to define pixel boundaries, eliminating the source of non-radiative recombination while preserving light extraction efficiency.
Solution Approach 2:
The patent replaces the permanent etched sidewall structures with temporary or replaceable electrical isolation layers and conductive patterns. These electrical definitions can be modified or removed without permanent structural changes to the active layer, providing flexibility in pixel design while avoiding the creation of harmful etched surfaces that cause non-radiative recombination.
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 maintains high internal quantum efficiency and improved light extraction even at small pixel sizes, ensuring adequate pixel contrast and efficient light emission in mini/micro LED arrays.
Implementation Method 1
first and second doped semiconductor layers and a junction or active layer between them that emit light at a nominal emission vacuum wavelength λ0 resulting from carrier recombination at the junction or active layer
Implementation Method 2
The outcoupling structures collect or redirect at least some of the light emitted by the active layer to exit the outcoupling structure and propagate away from the array
Data Source
AI summary
A light-emitting array includes a semiconductor LED structure, multiple outcoupling structures, multiple independent first electrical contacts, and second electrical contact(s). The LED structure extends contiguously over the array. The second electrical contacts are in electrical contact with the second semiconductor layer. Each outcoupling structure is a protruding portion of the second semiconductor layer. Each first electrical contact includes a circumscribed electrode layer opposite a corresponding outcoupling structure. Each outcoupling structure and corresponding first electrical contact define a corresponding discrete, circumscribed pixel region within the contiguous area of the array, each pixel region separate from the others. Some light emitted in the pixel region is collected or redirected by the outcoupling structure to exit the outcoupling structure and propagate away from the array.