Epitaxial Substrate Protrusions Enhance LED Light Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light emitting diodes (LEDs) face challenges in achieving uniform light intensity and efficiency due to total internal reflection and light concentration issues, leading to suboptimal illumination performance.
Innovation Solution
The epitaxial substrate is designed with a transparent sapphire base featuring protrusions and buffer layers with varying refractive indices, which reduce internal reflection and enhance light extraction and concentration, ensuring uniform light distribution by scattering and concentrating light laterally and centrally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional LED structure is used, then manufacturing is simple, but light extraction efficiency is low due to total internal reflection
Solution Approach 1:
The substrate surface is segmented into multiple protrusions with different heights and/or diameters, creating a non-uniform surface structure that divides the light extraction function across multiple elements, thereby reducing total internal reflection and improving light extraction efficiency
Solution Approach 2:
Different regions of the substrate surface are given different local properties through varying protrusion heights and diameters, allowing optimized light extraction at different locations while maintaining overall device functionality
2Illumination intensity
If conventional flat substrate is used, then structure is simple, but light intensity is non-uniform due to light concentration issues
Solution Approach 1:
The substrate surface is divided into multiple protrusions that scatter and redistribute light laterally, preventing light concentration in single areas and achieving more uniform light intensity distribution across the LED output
Solution Approach 2:
The substrate structure transitions from a two-dimensional flat surface to a three-dimensional non-uniform surface with varying protrusion heights and diameters, enabling enhanced light scattering and lateral light distribution in multiple spatial dimensions
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
This configuration significantly increases light extraction efficiency and uniformity, improving the overall illumination performance of LEDs by refracting and scattering light effectively across the substrate surfaces.
Implementation Method 1
buffer layers with varying refractive indices, which reduce internal reflection and enhance light extraction and concentration
Implementation Method 2
scattering and concentrating light laterally and centrally
Data Source
AI summary
An epitaxial substrate for growing a lighting emitting structure of a light emitting diode, includes a transparent base, a first buffer layer and a second buffer layer formed on the transparent base. The transparent base includes a first surface and a second surface opposite to the first surface. Plural protrusions are formed on the first surface of the transparent base. Each first buffer layer is formed on the outer surfaces of the plural protrusions. The second buffer layer fills in the recesses defined between two adjacent protrusions, and covers the first buffer layer. The refractive index of the first buffer layer is larger than that of the transparent base, and is less than that of the second buffer layer. This disclosure also relates a method for manufacturing the epitaxial substrate and a light emitting diode having the same.