LED Electrode Structure for Uniform Current Distribution

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Solution Overview

Problem

Conventional light emitting diodes (LEDs) face challenges in enhancing luminous efficiency and intensity, particularly due to current crowding and uneven luminescence distribution, which affect their performance and efficiency.

Innovation Solution

The design incorporates a light emitting device with a specific electrode structure that includes a first electrode part with a pad and expanded parts, and a second electrode part with branched finger electrodes, arranged to disperse current uniformly across the device, enhancing light extraction efficiency and reducing current crowding. This structure includes a current blocking layer and a conductive layer to optimize the contact between semiconductor layers and electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional LED electrode structure is used, then device simplicity is maintained, but current crowding occurs and luminous efficiency is reduced

Engineering Contradiction:
Improveluminous efficiencyVSAvoidelectrode structure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The electrode structure is segmented into multiple components: a first electrode part with a pad and expanded parts, and a second electrode part with multiple branched finger electrodes. This segmentation allows current to be distributed through multiple pathways rather than concentrated in a single location, reducing current crowding and improving luminous efficiency while maintaining reasonable structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the electrode structure are designed with different properties: the pad provides a large contact area for current injection, the expanded parts facilitate current distribution, and the branched finger electrodes extend current pathways to specific regions. This local optimization of electrode properties ensures uniform current distribution across the active layer, enhancing luminous efficiency without excessive complexity

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If conventional electrode arrangement is used, then manufacturing is simple, but luminescence distribution is uneven

Engineering Contradiction:
Improveluminescence uniformityVSAvoidelectrode fabrication complexity
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The second electrode part is divided into multiple branched finger electrodes that extend into different regions of the active layer. This segmentation creates multiple current injection points that promote uniform luminescence distribution across the device area, while the segmented structure can be fabricated using standard photolithography and electrode deposition techniques

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrode structure extends in multiple spatial dimensions: the pad provides a two-dimensional contact area, the expanded parts create intermediate distribution zones, and the branched finger electrodes extend in one dimension toward the active layer. This multi-dimensional electrode arrangement achieves uniform current distribution without requiring complex three-dimensional structures that would be difficult to manufacture

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

3Loss of energy

If larger electrode contact area is used, then current distribution improves, but device area increases

Engineering Contradiction:
Improvecurrent distribution efficiencyVSAvoiddevice area
Core Design Contradiction:
Loss of energyVSArea of stationary object

Solution Approach 1:

Instead of using a single large electrode contact area, the structure is segmented into a compact pad with expanded parts and multiple branched finger electrodes. This segmentation provides extensive current distribution pathways throughout the device area without requiring a single large electrode footprint, thus improving current distribution efficiency while maintaining a compact overall device area

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrode structure utilizes vertical and lateral dimensions efficiently: the pad and expanded parts are arranged in a compact footprint, while the branched finger electrodes extend vertically or laterally to reach different regions of the active layer. This dimensional optimization achieves superior current distribution without proportionally increasing the device's planar area

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

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 increases the luminous area and reduces driving currents, resulting in enhanced luminous efficiency and intensity, with improved uniformity in luminescence distribution and reduced current crowding.

Implementation Method 1

A light emitting diode (LED) is a type of semiconductor that is used as a light source or for sending and receiving a signal after converting electricity into an infrared ray or light, using the property of compound semiconductor.

Methodology Applied
Scientific EffectLight emitting diode (LED) electroluminescence: Electroluminescence

Data Source

PatentEP2482345B1Light emitting device
Publication Date: 2018.04.04 LG INNOTEK CO LTD
  • EP2482345B1 patent drawingFigure 1~2
  • EP2482345B1 patent drawingFigure 3
  • EP2482345B1 patent drawingFigure 4~5

AI summary

Disclosed is a light emitting device a substrate; a light emitting structure disposed on the substrate comprising a first conductive type semiconductor layer, an active layer and a second conductive type semiconductor layer; a conductive layer disposed on the second conductive type semiconductor layer; a first electrode part disposed on the conductive layer, with at least predetermined region in contact with the first conductive type semiconductor layer, passing through the conductive layer, the second conductive type semiconductor layer and the active layer; a first insulation layer disposed between the conductive layer and the first electrode part, between the second conductive type semiconductor layer and the first electrode part and between the active layer and the first electrode part; a second electrode part disposed on the conductive layer; and a second insulation layer disposed between the conductive layer and the second electrode part, wherein at least predetermined region of the second electrode part is in contact with the conductive layer, passing through the second insulation layer.