Micro LED Refractive-Index Electrode Structure for Light Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing micro LED elements face challenges in enhancing light extraction efficiency, which is crucial for improved display device performance.
Innovation Solution
A light-emitting device design featuring a stacked structure with a first electrode, a second electrode with a light-transmitting property, a first semiconductor layer, a second semiconductor layer, a light-emitting layer, and a light-transmitting portion, where the second electrode has a lower refractive index than the second semiconductor layer and a higher refractive index than the light-transmitting portion, and the surface of the second semiconductor layer in contact with the second electrode has an uneven structure, optimizing light emission and extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional micro LED element structure is used, then the device is simple to manufacture, but light extraction efficiency is low
Solution Approach 1:
The patent applies local quality by creating an uneven structure specifically at the interface between the second semiconductor layer and the second electrode, rather than modifying the entire device uniformly. This localized structural modification targets the specific region where light extraction occurs, improving light extraction efficiency without complicating the overall manufacturing process. The uneven structure is formed only where needed to enhance optical performance.
Solution Approach 2:
The patent changes the refractive index parameter by introducing a second electrode with a refractive index lower than the second semiconductor layer but higher than the light-transmitting portion. This parameter optimization creates favorable optical conditions for light extraction. Additionally, the uneven structure modifies the physical parameters of the interface, further enhancing light extraction efficiency.
2Reliability
If the refractive index of the second electrode is optimized for light extraction, then light extraction efficiency improves, but device complexity increases
Solution Approach 1:
The complexity is localized to the interface region between the second semiconductor layer and the second electrode. The uneven structure and specific refractive index requirements apply only to this localized area, not to the entire device. This allows optimization of light extraction efficiency without requiring complex modifications throughout the entire device structure.
Solution Approach 2:
The patent employs composite material strategy by selecting a second electrode material that combines specific optical properties (refractive index between the second semiconductor layer and light-transmitting portion) with electrical conductivity requirements. This composite approach allows simultaneous satisfaction of optical and electrical performance requirements without excessive device complexity.
3Illumination intensity
If light reflection at the interface is reduced, then light output increases, but parasitic capacitance may increase
Solution Approach 1:
The patent optimizes the refractive index parameter of the second electrode to balance optical and electrical performance. By selecting a material with refractive index lower than the second semiconductor layer but higher than the light-transmitting portion, the patent reduces light reflection and enhances light output while attempting to control parasitic capacitance through proper material selection and layer thickness optimization.
Solution Approach 2:
The uneven structure is applied locally at the interface region to reduce light reflection, while the overall device structure and electrode design are optimized to minimize parasitic capacitance. This localized approach allows improvement of light output without proportionally increasing parasitic capacitance throughout the entire device.
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 enhances light extraction efficiency by reducing light reflection at the interface between the second semiconductor layer and the second electrode, improving light reflection and refraction, thereby increasing the overall light output and reducing parasitic capacitance.
Implementation Method 1
reducing light reflection at the interface between the second semiconductor layer and the second electrode
Implementation Method 2
improving light reflection and refraction
Implementation Method 3
a refractive index of the second electrode is lower than a refractive index of the second semiconductor layer and is higher than a refractive index of the light-transmitting portion
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A light-emitting device includes: a first electrode; a second electrode has a light-transmitting property; a first semiconductor layer that is provided between the first electrode and the second electrode; a second semiconductor layer that is provided between the first semiconductor layer and the second electrode and is in contact with the second electrode; a light-emitting layer that is provided between the first semiconductor layer and the second semiconductor layer; and a light-transmitting portion provided on a side of the second electrode opposite to the second semiconductor layer, wherein light generated in the light-emitting layer is emitted from side of the second electrode, a refractive index of the second electrode is lower than a refractive index of the second semiconductor layer and is higher than a refractive index of the light-transmitting portion, and a surface of the second semiconductor layer in contact with the second electrode has an uneven structure.