LED Light Extraction via Reflective and Current Block Layers
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Solution Overview
Problem
LED devices face challenges in achieving high brightness and light-emitting efficiency due to inadequate current spread characteristics and light extraction efficiency.
Innovation Solution
The proposed LED device incorporates a current block layer, a reflective layer, and a protection layer to enhance current spread and light extraction, featuring a structure with a conductive type semiconductor layer, an active layer, and a p-type semiconductor layer, along with a transparent electrode layer and encapsulation layers to improve reliability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional LED structure is used, then device simplicity is maintained, but current spread characteristics and light extraction efficiency are insufficient
Solution Approach 1:
The LED device is divided into multiple functional layers: emission structure, current block layer, reflective layer, protection layer, and electrode layer. Each layer performs a specific function to improve overall performance. The current block layer segments the current path to enhance spread characteristics, while the reflective layer segments light paths to improve extraction efficiency.
Solution Approach 2:
Different regions of the LED device are given different properties. The current block layer is positioned in specific areas to control current distribution locally. The reflective layer is applied in regions where light extraction enhancement is most needed. This local optimization allows improved performance without uniformly increasing complexity throughout the entire device.
2Reliability
If current spread characteristics are improved through additional layers, then light extraction efficiency increases, but manufacturing complexity increases
Solution Approach 1:
Multiple functions are merged into single layers where possible. The current block layer serves both as a current management structure and as a base for the reflective layer. The protection layer simultaneously protects the reflective layer and provides a substrate for the electrode layer. This merging reduces the total number of discrete manufacturing steps while maintaining the beneficial multi-layer structure for improved emission reliability.
3Illumination intensity
If reflective layer is added to improve light extraction, then brightness increases, but device complexity increases
Solution Approach 1:
The reflective layer is designed to serve multiple purposes: it reflects extracted light to enhance brightness, provides a protective interface between the current block layer and protection layer, and serves as an electrical connection path in some configurations. The protection layer simultaneously protects the reflective layer and provides mechanical support for subsequent electrode layers. This multi-functionality allows brightness enhancement without proportionally increasing device complexity.
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 effectively improves current spread characteristics and light extraction efficiency, leading to higher emission reliability and brightness of the LED device.
Implementation Method 1
a reflective layer on the current block layer
Implementation Method 2
an active layer
Data Source
AI summary
A light-emitting device includes an emission structure, a current block layer on the emission structure, a reflective layer on the current block layer, a protection layer that covers the reflective layer, and an electrode layer on the protection layer.