LED Transparent Conductive Layer Local Quality Current Control

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Solution Overview

Problem

Current light emitting diodes (LEDs) face limitations in design, performance, and manufacturing, particularly in achieving improved light efficiency.

Innovation Solution

A light emitting device with a novel structure comprising a conductive support layer, a transparent conducting layer with regions of different electrical conductivity, a light emitting structure layer with semiconductor layers of different types, and an electrode that vertically overlaps the lower conductivity region, along with a manufacturing method that forms these layers using various deposition processes and materials to optimize current flow and light emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a transparent conducting layer with high electrical conductivity is used to ensure good current flow, then electrical conductivity is improved, but light absorption increases reducing light efficiency

Engineering Contradiction:
Improveelectrical conductivityVSAvoidlight absorption
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The transparent conducting layer is divided into a first region with first electrical conductivity and a second region with second electrical conductivity. The first region (with higher conductivity) is positioned to overlap the electrode for optimal current injection, while the second region (with lower conductivity) is positioned in the light emission area to minimize light absorption. This local differentiation of conductivity properties resolves the contradiction between ensuring good electrical contact and minimizing light loss.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If the transparent conducting layer is made thinner to reduce light absorption, then light efficiency is improved, but electrical conductivity decreases

Engineering Contradiction:
Improvelight absorptionVSAvoidelectrical conductivity
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

Instead of uniformly thinning the transparent conducting layer, the invention applies different thicknesses or conductivities to different regions. The first region maintains sufficient thickness for good electrical conductivity where current injection is needed, while the second region is made thinner to reduce light absorption in the emission area, thus resolving the contradiction between electrical performance and optical efficiency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The transparent conducting layer is segmented into functionally distinct first and second regions with different conductivity characteristics. This segmentation allows each region to be optimized for its specific function: the first region for electrical conduction and the second region for light transmission, thereby resolving the trade-off between conductivity and light efficiency.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the electrode is positioned to overlap the high conductivity region for better current flow, then electrical conductivity is improved, but light absorption in that region increases

Engineering Contradiction:
Improveelectrical conductivityVSAvoidlight emission intensity
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The electrode is positioned to overlap the first region with higher electrical conductivity for optimal current injection. Simultaneously, the second region with lower conductivity is positioned in the light emission area to minimize light absorption. This spatial separation of high-conductivity and low-absorption zones resolves the contradiction between electrical performance and light emission intensity.

Inventive Principle:
Principle #3Local quality

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 enhances light efficiency by controlling current flow and minimizing light absorption in the transparent conducting layer, resulting in improved light emission and efficiency.

Implementation Method 1

a transparent conducting layer comprising a first region having first electrical conductivity and a second region having second electrical conductivity less than the first electrical conductivity

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

a light emitting structure layer comprising a first conductive type semiconductor layer, a second conductive type semiconductor layer, and an active layer between the first conductive type semiconductor layer and the second conductive type semiconductor layer

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 3

the first transparent conducting layer and the second transparent conducting layer are formed of the same material as each other using deposition processes or deposition process conditions different from each other

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentEP2337098B1Light emitting device
Publication Date: 2019.06.19 LG INNOTEK CO LTD
  • EP2337098B1 patent drawingFigure 1~2
  • EP2337098B1 patent drawingFigure 3~4
  • EP2337098B1 patent drawingFigure 5~6

AI summary

A light emitting device includes a transparent conductive layer formed adjacent one of two semiconductor layers (20,40) having an active layer (30) therebetween. The transparent conductive layer includes first (61) and second (62) transparent conductive regions with different electrical conductivities. The difference in electrical conductivities controls an amount or flow rate of current into the semiconductor layer adjacent the transparent conductive layer, and an electrode is at least partial aligned with the second transparent conductive region.