LED Multi-Pattern Structure for Light Extraction
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Solution Overview
Problem
Conventional semiconductor light emitting devices using sapphire substrates face challenges in efficiently extracting light due to refractive index differences, resulting in low light extraction efficiency, and existing corrugated structures are difficult and costly to implement.
Innovation Solution
A multiple pattern structure is formed on the substrate, with a second corrugated pattern created between protrusions of a first pattern, using dry etching processes, to enhance light extraction efficiency by maximizing refractive index differences and light path changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single corrugated structure is formed on the sapphire substrate to improve light extraction efficiency, then light extraction efficiency increases, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent divides the single corrugated structure into multiple independent corrugated patterns (first pattern and second pattern) with different orientations and geometries. The first pattern has corrugations in a first direction while the second pattern has corrugations in a second direction different from the first direction. This segmentation allows each pattern to extract light in different directions, improving overall light extraction efficiency while maintaining manageable manufacturing complexity through modular design
Solution Approach 2:
Different regions of the substrate surface are given different local qualities through the first and second corrugated patterns. The first pattern region optimizes for light extraction in one direction while the second pattern region optimizes for light extraction in another direction. This local differentiation allows the structure to handle light extraction requirements in multiple directions simultaneously, resolving the contradiction between improving light extraction and maintaining structural simplicity
2Loss of energy
If a corrugated structure is formed on the sapphire substrate to maximize refractive index differences, then light extraction efficiency improves, but manufacturing difficulty and cost increase
Solution Approach 1:
The manufacturing process is segmented into two separate dry etching steps, where the first corrugated pattern is formed in a first direction and the second corrugated pattern is formed in a second direction. This segmentation of the manufacturing process into discrete, sequential steps makes the complex multi-directional corrugated structure manufacturable using standard semiconductor fabrication techniques, reducing both manufacturing difficulty and cost while achieving maximum light extraction efficiency
Solution Approach 2:
The patent replaces mechanical or manual structuring methods with dry etching processes to form the corrugated patterns. This substitution of manufacturing methodology enables precise control over the corrugated structure geometry and orientation, making the complex multi-pattern structure economically manufacturable while maximizing light extraction through controlled refractive index differences at the corrugated interfaces
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 multiple pattern structure increases light extraction efficiency by approximately 70% compared to conventional flat substrates and 30.8% compared to corrugated structures, improving optical output.
Implementation Method 1
anatomical structure that can increase light extraction efficiency by maximizing refractive index differences
Implementation Method 2
a corrugate refractive interface is formed on a lower side of the active layer 22 to be able to extract a portion of light in the horizontal direction
Data Source
Figure 1~2A
Figure 2B~2B(d)
Figure 3~4B
AI summary
Provided is a semiconductor light emitting device having a multiple pattern structure that can greatly increase light extraction efficiency. The semiconductor light emitting device includes a substrate (31) and a semiconductor layer (34), an active layer (35), and an electrode layer (37) formed on the substrate (31), a first pattern (32) formed in a corrugated structure between the substrate (31) and the semiconductor layer (34), and a second pattern (33) formed in a corrugated structure on the corrugated structure of the first pattern (32).