Irregular Metal Filter Light Extraction LED

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Solution Overview

Problem

Current light emitting devices face challenges in enhancing light extraction efficiency and heat dissipation, particularly in semiconductor LEDs, where the existing electrode structures and materials do not adequately address the need for improved conductivity and mechanical strength.

Innovation Solution

A light emitting device structure featuring a metal support as a second electrode, a transparent conductive layer with a metal filter in an irregular pattern, and a passivation layer, which enhances light extraction and heat dissipation by using materials like aluminum or titanium for the metal filter and conductive layers, and includes a bonding layer and reflective layer for adhesion and light reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional electrode structure is used, then the device structure is simple, but light extraction efficiency is insufficient

Engineering Contradiction:
Improvestructure simplicityVSAvoidlight extraction efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The electrode structure is divided into multiple segments: a transparent conductive layer with patterned openings, a reflective layer in the openings, and a metal support. This segmentation allows each component to perform its specific function - the transparent conductive layer maintains electrical conductivity while allowing light passage, the reflective layer extracts light through reflection, and the metal support provides mechanical strength and additional electrode function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The device employs composite material structures including transparent conductive oxides combined with metal reflective layers, and semiconductor layers with specific conductivity types. These composite materials provide multiple properties simultaneously - electrical conductivity, optical transparency, and reflective characteristics - resolving the contradiction between structural simplicity and light extraction efficiency.

Inventive Principle:
Principle #40Composite materials

2Device complexity

If existing electrode materials are used, then material selection is simple, but heat dissipation is insufficient

Engineering Contradiction:
Improvematerial selection complexityVSAvoidheat dissipation
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The metal support serves multiple functions simultaneously: it acts as a mechanical support structure, a heat dissipation pathway due to its high thermal conductivity, and a second electrode for electrical connection. This multi-functionality resolves the contradiction by adding heat dissipation capability without requiring separate dedicated heat management materials.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The transparent conductive layer and reflective layer structure serves as an intermediary between the light emitting structure and the metal support, enabling both optical functions (light extraction) and thermal functions (heat dissipation) to be achieved through the layered architecture without direct compromise to either performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If a regular pattern metal filter is used, then manufacturing is easier, but light extraction efficiency is reduced

Engineering Contradiction:
Improvepattern fabrication easeVSAvoidlight extraction efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The metal filter employs an asymmetric irregular pattern rather than a regular symmetric pattern. This asymmetry creates varied light reflection paths and angles, improving light extraction efficiency by preventing uniform light blocking while still maintaining manufacturability through standard photolithography and etching processes that can accommodate irregular patterns.

Inventive Principle:
Principle #4Asymmetry

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 proposed structure significantly improves light extraction efficiency and heat dissipation, allowing for higher luminance and mechanical strength, making it suitable for various applications including LED lighting and display devices.

Implementation Method 1

a metal filter of an irregular pattern on the light emitting structure

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a transparent conductive layer disposed on the first conductivity type semiconductor layer and the metal filter

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

a metal support under the light emitting structure, the metal support adapted to serve as a second electrode

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

a passivation layer is disposed at a side of the light emitting structure

Methodology Applied
Scientific EffectPhysical barrier protection:

Implementation Method 5

The light emitting device, such as a light emitting diode of III-V group or II-VI group compound semiconductor

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2541627B1Light emitting device and lighting system with the same
Publication Date: 2019.08.28 LG INNOTEK CO LTD
  • EP2541627B1 patent drawingFigure 1A
  • EP2541627B1 patent drawingFigure 1B
  • EP2541627B1 patent drawingFigure 1C

AI summary

Embodiments provide a light emitting device including a light emitting structure having a first conduction type semiconductor layer (122), an active layer (124), and a second conduction type semiconductor layer (126), a metal filter (180) of an irregular pattern on the light emitting structure, and openings between the irregular patterns in the metal filter.