LED Electrode Segmentation for Uniform Current Diffusion

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Solution Overview

Problem

Fluorescent lamps have a short lifespan and are not environmentally friendly, leading to a need for more efficient and sustainable light sources, with existing semiconductor light emitting devices facing challenges in achieving high brightness and uniform current diffusion for improved light emission efficiency.

Innovation Solution

A light emitting device with a substrate having a patterned sapphire structure and a specific electrode configuration, including a bonding layer and insulating layers, to enhance thermal stability and light extraction efficiency, while allowing for easy bonding and current management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If fluorescent lamps are used for illumination, then they provide sufficient brightness, but they have short lifespan and are not environmentally friendly

Engineering Contradiction:
ImprovebrightnessVSAvoidlifespan
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent transitions from fluorescent lamp technology to LED technology, fundamentally changing the light generation mechanism from gas discharge to electroluminescence in semiconductor materials. This parameter change enables longer lifespan and environmental friendliness while maintaining or improving brightness through optimized LED chip design and phosphor conversion layers.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical/electrical gas discharge system of fluorescent lamps with a semiconductor-based electroluminescence system. The LED chip structure with n-type and p-type semiconductor layers substituted the fluorescent coating and gas fill, achieving superior reliability and environmental performance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Use of energy by moving object

If conventional LED structures are used, then they provide energy efficiency, but they fail to achieve uniform current diffusion and high brightness

Engineering Contradiction:
Improvepower consumptionVSAvoidbrightness
Core Design Contradiction:
Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The patent applies local quality by creating a patterned electrode structure with multiple finger-like electrodes distributed across the LED chip surface. This local electrode arrangement ensures uniform current diffusion across different regions of the active layer, preventing current crowding and enabling homogeneous light emission throughout the device, thereby achieving high brightness while maintaining energy efficiency.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If simple electrode configuration is used in LEDs, then manufacturing is easier, but current diffusion is non-uniform and light emission efficiency is reduced

Engineering Contradiction:
Improveelectrode configurationVSAvoidlight emission efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent segments the electrode structure into multiple finger-like electrodes arranged in a pattern across the LED chip. This segmentation divides the current path into multiple parallel channels, ensuring uniform current distribution through the active layer. The segmented electrode design maintains manufacturing simplicity while dramatically improving light emission efficiency through enhanced current diffusion uniformity.

Inventive Principle:
Principle #1Segmentation

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 results in improved luminous efficacy, stability, and reliability of the light emitting device, addressing the limitations of fluorescent lamps and enhancing the performance of semiconductor light emitting devices for high-brightness applications.

Implementation Method 1

an active layer formed on a first region of the n-type semiconductor layer

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a reflective layer formed on the dielectric layer

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

a bonding layer and insulating layers, to enhance thermal stability

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 4

a bonding layer and insulating layers

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP2439795B1Light emitting device
Publication Date: 2019.03.20 LG INNOTEK CO LTD
  • EP2439795B1 patent drawingFigure 1
  • EP2439795B1 patent drawingFigure 2(a)~2(b)
  • EP2439795B1 patent drawingFigure 3

AI summary

Disclosed is a light emitting structure comprising a first semiconductor layer, a second semiconductor layer, and an active layer disposed on between the first and second semiconductor layers, a first electrode electrically connected to the first semiconductor layer and a second electrode electrically connected to the second semiconductor layer. The first semiconductor layer is formed, at an edge portion thereof, with a hole, in which a portion of the first electrode is arranged.