LED Electrode Offset Wavy Pattern Light Extraction

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Solution Overview

Problem

Existing semiconductor light emitting diodes face challenges in maximizing light output power due to light absorption and reflection by electrode portions, leading to decreased light extraction efficiency, and increasing the distance between electrodes to mitigate this issue results in higher resistance and forward voltage.

Innovation Solution

A semiconductor light emitting diode design featuring an upper electrode portion and intermediate electrode portions positioned in an offset, wavy pattern on the light extraction side, with a metal reflective layer, to enhance light extraction efficiency while maintaining low forward voltage by concentrating current density and increasing recombination probability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the distance between the electrode portion on the light extraction side and the paired electrode portion is increased to reduce light blockage, then light extraction efficiency is improved, but resistance increases and forward voltage increases

Engineering Contradiction:
Improvelight extraction efficiencyVSAvoidforward voltage
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The electrode structure is segmented into three parts: a first electrode portion on the light extraction side, a second electrode portion paired with it, and a third electrode portion positioned between them. This segmentation allows the third electrode to serve as an intermediate light extraction path while maintaining shorter distances between electrodes, thus reducing resistance while improving light extraction efficiency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a new spatial dimension by adding the third electrode portion at a different position relative to the first and second electrode portions. This dimensional arrangement creates multiple light extraction paths and reduces the direct distance between opposing electrodes, simultaneously improving light extraction and reducing resistance

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Power

If the electrode portion is positioned to maximize light extraction, then light output power increases, but the distance between electrodes increases causing higher resistance

Engineering Contradiction:
Improvelight output powerVSAvoidresistance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The electrode system is divided into three separate electrode portions that work together. The third electrode portion positioned between the first and second electrodes provides additional light extraction pathways without requiring increased distance between the main electrode pairs, thus maintaining low resistance while maximizing light output power

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The third electrode portion acts as an intermediary element between the first and second electrodes. It mediates the light extraction process by providing intermediate extraction paths and serves as an electrical conductor that maintains low resistance connections, enabling both high light output and low resistance simultaneously

Inventive Principle:
Principle #24Intermediary (Mediator)

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 described configuration improves light output power while maintaining relatively low forward voltage by optimizing the positional relationship of electrode portions and using a reflective layer to enhance light collection, achieving higher recombination probabilities and current density.

Implementation Method 1

a metal reflective layer, to enhance light extraction efficiency while maintaining low forward voltage

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

When a voltage is applied to such an LED, light is generated in the active layer

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2398077B1Semiconductor light emitting diode and method of producing same
Publication Date: 2019.08.07 DOWA ELECTRONICS MATERIALS CO LTD
  • EP2398077B1 patent drawingFigure 1A~1B
  • EP2398077B1 patent drawingFigure 2A~2C
  • EP2398077B1 patent drawingFigure 3A~3H

AI summary

The present invention provides: a semiconductor light emitting diode that improves light output power while maintaining a relatively low forward voltage by positioning an upper electrode portion as an electrode portion on the light extraction side and an intermediate electrode portion paired with the upper electrode portion in appropriate positional relationship; and a method of producing the semiconductor light emitting diode. Specifically, the present invention provides a semiconductor light emitting diode comprising: a support substrate 2; an intermediate layer 3 including an intermediate electrode portion 3a, a second conductive semiconductor layer 4, an active layer 5, a first conductive semiconductor layer 6 and an upper electrode portion 7 sequentially disposed on the upper surface side of the support substrate in this order; and a lower electrode layer 8 provided on the lower surface side of the support substrate 2, wherein: the intermediate layer 3 has at least one intermediate electrode portion 3a extending linearly or in an island-like shape; and the upper electrode portion 7 and the intermediate electrode portion 3a are disposed, in a view obtained by projecting these electrode portions 7, 3a on an imaginary plane in parallel with the upper surface of the support substrate 2, respectively, in a positional relationship that these electrode portions 7, 3a are offset from each other and a contour of at least one of the upper electrode portion 7 and the intermediate electrode portion 3a extends in a wavy winding manner with a predetermined amplitude such that an inter-contour distance d between contour lines of the upper electrode portion 7 and the intermediate electrode portion 3a facing each other partially decreases.