Reflective Insulating Layer for High-Efficiency LED Light Extraction
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Solution Overview
Problem
Conventional light emitting diodes (LEDs) using Group-III-element nitrides face challenges with Ag reflection layers, including aggregation and current leakage, which affect light extraction efficiency and stability, and have limitations in reflectance.
Innovation Solution
A high-efficiency LED structure is developed with a reflective insulating layer and a transparent electrode layer, where the reflective insulating layer, potentially a DBR, enhances light reflectance and light extraction by covering the transparent electrode layer and exposing it to reduce light loss, and an insulating layer is used to distribute current laterally, reducing concentration and improving stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If Ag is used as a reflection layer, then light reflectance is improved, but Ag aggregation and current leakage occur during heating and operation
Solution Approach 1:
The patent changes the material parameter from Ag (metal) to transparent insulating material, fundamentally altering the physical and chemical properties to eliminate aggregation and current leakage while maintaining optical functionality
Solution Approach 2:
The transparent insulating layer acts as an intermediary between the electrode and the support substrate, providing both electrical insulation and optical reflection functions that prevent direct contact issues between Ag and the substrate
2Illumination intensity
If Ag is used as a reflection layer, then light reflectance is improved, but current leakage occurs due to Ag atom migration
Solution Approach 1:
The patent changes the material from conductive Ag to insulating material, fundamentally altering the electrical property to eliminate current leakage while maintaining optical reflection capability
Solution Approach 2:
The patent extracts the harmful electrical conductivity property from the reflection layer, separating the optical function (reflection) from the electrical function (conduction) to eliminate current leakage
3Productivity
If current concentration occurs in the LED structure, then light emitting performance is improved, but static electricity resistance deteriorates
Solution Approach 1:
The transparent insulating layer serves as a mediator that distributes electrical stress laterally, preventing direct current concentration paths while allowing controlled light extraction, thus protecting against static electricity damage
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 solution increases light extraction efficiency and reflectance, stabilizes the LED structure, and prevents current concentration, leading to improved light emitting performance and reduced static electricity resistance.
Implementation Method 1
a reflective insulating layer formed to cover the transparent electrode layer, the reflective insulating layer reflecting the light emitted toward the support substrate from the active layer
Implementation Method 2
an insulating layer is used to distribute current laterally, reducing concentration and improving stability
Data Source
AI summary
A high-efficiency light emitting diode including: a semiconductor stack positioned on a support substrate, including a p-type compound semiconductor layer, an active layer, and an n-type compound semiconductor layer; an insulating layer disposed in an opening that divides the p-type compound semiconductor layer and active layer; a transparent electrode layer disposed on the insulating layer and the p-type compound semiconductor layer; a reflective insulating layer covering the transparent electrode layer, to reflect light from the active layer away from the support substrate; a p-electrode covering the reflective insulating layer; and an n-electrode is formed on top of the n-type compound semiconductor layer. The p-electrode is electrically connected to the transparent electrode layer through the insulating layer.