LED P-type Electrode Sidewall Extension for Light-emitting Area
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Solution Overview
Problem
Conventional light-emitting diodes (LEDs) suffer from reduced luminous efficiency due to the current expansion strip of the P-type electrode covering part of the light-emitting area, which decreases the effective light-emitting area and efficiency.
Innovation Solution
The current expansion strip of the P-type electrode is disposed on the N-type semiconductor layer without overlapping with the P-type semiconductor layer, allowing the light-emitting area to remain unobstructed, while maintaining even current distribution through a transparent conductive layer and current blocking layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the current expansion strip of the P-type electrode is disposed on the p-doped semiconductor layer to ensure even current distribution, then the current distribution is improved, but the light-emitting area is decreased and luminous efficiency is reduced
Solution Approach 1:
The current expansion strip is extended from the traditional planar configuration on the p-doped semiconductor layer to a three-dimensional configuration that includes sidewall portions extending along the vertical dimension. This allows the current expansion function to be achieved without occupying additional lateral space that would reduce the light-emitting area.
Solution Approach 2:
The current expansion strip is divided into multiple segments: a first portion on the p-doped semiconductor layer, a second portion on the insulating layer, and sidewall portions extending along the sidewalls of the light-emitting layer. This segmentation allows the current expansion function to be distributed across different spatial locations without concentrating the electrode in one area that would block light emission.
2Reliability
If the current expansion strip covers part of the light-emitting area to ensure even current distribution, then the current distribution is improved, but the luminous efficiency is reduced
Solution Approach 1:
The current expansion strip utilizes the vertical dimension by extending sidewall portions along the sidewalls of the light-emitting layer. This three-dimensional configuration provides additional current distribution pathways without occupying lateral space that would block light emission and reduce luminous efficiency.
Solution Approach 2:
An insulating layer is introduced as an intermediary medium between the current expansion strip and the light-emitting layer. The insulating layer allows the current expansion strip to extend underneath and along the sidewalls of the light-emitting layer, providing current distribution functionality while preventing direct contact that would block light emission and reduce luminous efficiency.
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 the luminous efficiency of LEDs by reducing the light-shielding area covered by the P-type electrode, improving current distribution, and maintaining the benefits of the current expansion strip.
Implementation Method 1
a transparent conductive layer is disposed on a partial upper surface of the P-type semiconductor layer, and a part of the transparent conductive layer is disposed between the current blocking layer and the P-type electrode
Implementation Method 2
When the light-emitting diode is switched on, electrons are able to recombine with holes at the interface between the p-doped semiconductor layer and the n-doped semiconductor layer, releasing energy in the form of photons. This effect is called the electroluminescence of the light-emitting diode.
Data Source
AI summary
A light-emitting diode is provided. The light-emitting diode includes an N-type semiconductor layer, a light-emitting layer and a P-type semiconductor layer. A P-type electrode includes a body part and an extension part, wherein the body part is disposed on a corner of an upper surface of the P-type semiconductor layer and the extension part extends from the body part onto the N-type semiconductor layer along a sidewall of the P-type semiconductor layer adjacent to the N-type semiconductor layer. An N-type electrode is disposed on the N-type semiconductor layer. Moreover, a current blocking layer is disposed under the P-type electrode. A transparent conductive layer is disposed on a partial upper surface of the P-type semiconductor layer.