Light-emitting device with segmented metal layer for voltage reduction

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Solution Overview

Problem

Current light-emitting devices face challenges in lowering operating voltage and improving light extraction efficiency.

Innovation Solution

The light-emitting device design includes a light-emitting structure with specific semiconductor layers, a reflective electrode, and metal layers, along with insulating and contact layers, which are strategically arranged to reduce operating voltage and enhance light extraction efficiency through improved current spreading and light reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a conventional light-emitting device structure is used, then the device can be manufactured with standard processes, but the operating voltage remains high and light extraction efficiency is limited

Engineering Contradiction:
Improveoperating voltageVSAvoiddevice structure
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The device is segmented into functionally distinct regions: a first metal layer with a first region for direct semiconductor contact and a second region for light extraction, separated by a first insulating layer. This segmentation allows independent optimization of electrical and optical functions, reducing operating voltage while maintaining light extraction efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first metal layer extends in multiple dimensions with its second region protruding laterally beyond the light-emitting structure. This dimensional extension creates additional light extraction pathways without increasing vertical complexity, thereby improving light extraction while keeping the device structure manageable.

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

2Illumination intensity

If the metal layer is extended to improve light extraction, then light extraction efficiency increases, but the device structure becomes more complex

Engineering Contradiction:
Improvelight extraction efficiencyVSAvoidmetal layer configuration
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The first metal layer serves multiple functions simultaneously: it provides electrical connection through its first region, acts as a reflective electrode for light extraction through its second region, and maintains structural integrity. This multi-functionality reduces the need for additional separate components, thereby improving light extraction without proportionally increasing device complexity.

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

Solution Approach 2:

The electrical connection function and light extraction function are merged into a single first metal layer structure. The first region handles electrical connection while the second region handles light extraction, combining what could have been separate components into one integrated element, thus improving light extraction efficiency without linearly increasing complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If insulating layers are added to isolate metal layers, then electrical isolation is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveelectrical isolationVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

A first insulating layer is introduced as an intermediary between the first metal layer and second metal layer. This thin intermediate layer provides necessary electrical isolation and prevents short circuits while being compatible with standard semiconductor manufacturing processes, thus improving reliability without significantly complicating manufacturing.

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

This configuration effectively lowers the operating voltage and increases light extraction efficiency, leading to improved performance in light-emitting devices.

Implementation Method 1

a reflective electrode under the light-emitting structure

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

The LED converts electrical signals into the form of light such as infrared light, ultra-violet light, and visible light by using the characteristic of a compound semiconductor

Methodology Applied
Scientific EffectLight-emitting diode effect: Light Emitting Diode

Data Source

PatentEP2860771B1Light-emitting device
Publication Date: 2020.08.05 LG INNOTEK CO LTD
  • EP2860771B1 patent drawingFigure 1~2
  • EP2860771B1 patent drawingFigure 3~4
  • EP2860771B1 patent drawingFigure 5~6

AI summary

A light-emitting device, according to one embodiment, comprises: a light-emitting structure comprising a first conductive semiconductor layer, an active layer which is underneath the first conductive semiconductor layer, and a second conductive semiconductor layer which is underneath the active layer; a reflective electrode which is arranged under the light-emitting structure; a first metal layer which is arranged under the reflective electrode and is electrically connected to the second conductive semiconductor layer; a second metal layer which is arranged under the reflective electrode and is insulated from the first metal layer; and a contact portion for electrically connecting the second metal layer and the first conductive semiconductor layer.