Micro LED Surface Microstructure Layout for Uniform Light Emission
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Solution Overview
Problem
Micro LED displays face issues with light emission uniformity due to random distribution of threading dislocation defects and irregular microstructure cut sections during the cutting process, which affects light extraction efficiency and scattering mode.
Innovation Solution
A light emitting device with an epitaxial structure and surface microstructures arranged in non-perpendicular directions to the surrounding wall surface, ensuring that the cutting shape of the surface microstructures at the cut section exhibits irregularities in size or depth, thereby improving light emission uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If patterned-sapphire substrate (PSS) is used for epitaxy to reduce threading dislocation defects, then the number of defects is reduced, but the microstructure cut sections become random and different, destroying light emission uniformity
Solution Approach 1:
The patent applies asymmetry by arranging surface microstructures in non-perpendicular directions relative to the surrounding wall surface of the epitaxial structure. This asymmetric arrangement ensures that after cutting, the microstructure cut sections remain consistent and do not exhibit random variations, thereby maintaining light emission uniformity while preserving the defect-reduction benefits of PSS epitaxy
Solution Approach 2:
The patent implements local quality by specifically designing the arrangement of surface microstructures on the light emitting surface with particular directional characteristics. The microstructures are arranged along specific directions that are not perpendicular to the surrounding wall surface, creating localized structural qualities that ensure consistent light extraction and scattering behavior after cutting
2Ease of manufacture
If surface microstructures are arranged perpendicular to the surrounding wall surface, then the structure is simple and easy to manufacture, but the light emission uniformity deteriorates due to random microstructure cut sections
Solution Approach 1:
The patent deliberately introduces asymmetry by arranging surface microstructures in non-perpendicular directions relative to the surrounding wall surface. This asymmetric configuration increases manufacturing complexity slightly but ensures that the microstructure cut sections after cutting are consistent and predictable, thereby achieving uniform light emission across all micro LEDs
Data Source
AI summary
A light emitting device including an epitaxial structure and a plurality of surface microstructures is provided. The epitaxial structure has a light emitting surface and a surrounding wall surface. The surrounding wall surface surrounds and is connected to the light emitting surface. The plurality of surface microstructures are separately arranged on the light emitting surface along a plurality of directions. The plurality of directions are not perpendicular to the surrounding wall surface. A light emitting device substrate including a plurality of the light emitting device is also provided.