Light Emitting Device Cell Segmentation for Luminance

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Solution Overview

Problem

Current light emitting devices face challenges in achieving high luminance and efficiency due to limitations in light extraction and electrical properties, particularly in the design of semiconductor layers and packaging technologies.

Innovation Solution

The light emitting device incorporates a substrate with multiple light emitting cells connected by a connection electrode, featuring a reflective layer on the second conductive type semiconductor layer and a conductive layer with light transmittance, along with insulating layers and electrode units, to enhance optical and electrical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If multiple light emitting cells are connected in series to increase luminance, then light extraction efficiency improves, but device complexity increases due to multiple connection electrodes and insulating layers

Engineering Contradiction:
ImproveluminanceVSAvoiddevice complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The light emitting device is divided into multiple light emitting cells (first, second, third cells) with distinct semiconductor layers and active regions. Each cell can be independently controlled through separate electrode connections, allowing series configuration to achieve higher luminance while maintaining manageable complexity through modular segmentation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a vertical stacking dimension by disposing insulating layers between adjacent light emitting cells and using connection electrodes that extend through multiple cell layers. This three-dimensional arrangement allows series connection of multiple cells without significantly increasing planar footprint, thereby increasing luminance while controlling device complexity

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

2Reliability

If the second conductive type semiconductor layer width is increased to improve electrical conductivity, then electrical properties improve, but light extraction efficiency may deteriorate due to reduced light emission area

Engineering Contradiction:
Improveelectrical conductivityVSAvoidlight extraction efficiency
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent applies different width specifications to different semiconductor layers: the first conductive type semiconductor layer has a first width, the second conductive type semiconductor layer has a second width, and the active layer has a third width. This local quality differentiation allows optimization of electrical conductivity in conductive layers while preserving light extraction efficiency in the active layer region

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent deliberately creates asymmetric width relationships among semiconductor layers, where the second conductive type semiconductor layer width may differ from the first conductive type semiconductor layer width. This asymmetric design enables independent optimization of electrical transport paths versus light emission areas, resolving the contradiction between electrical conductivity and light extraction efficiency

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

This configuration improves light extraction efficiency and electrical conductivity, leading to enhanced internal quantum efficiency and reliability of the light emitting device.

Implementation Method 1

a reflective layer disposed on the second conductive type semiconductor layer

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

a conductive layer being disposed between the reflective layer and the second conductive type semiconductor layer and having light-transmittance

Methodology Applied
Scientific EffectLight transmission:

Implementation Method 3

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

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2944862B1Light emitting device and lighting device including the light emitting device
Publication Date: 2021.11.03 SUZHOU LEKIN SEMICON CO LTD
  • EP2944862B1 patent drawingFigure 1
  • EP2944862B1 patent drawingFigure 2
  • EP2944862B1 patent drawingFigure 3A

AI summary

Disclosed is a light emitting device (100) including a plurality of light emitting cells (P1,P2,P3) disposed on a substrate (110), at least one connection electrode (150-1,150-2) connecting the light emitting cells (P1,P2,P3), and a first insulating layer disposed between adjacent light emitting cells (P1,P2,P3), wherein each of the light emitting cells (P1,P2,P3) includes a light emitting structure (120) including first and second conductive type semiconductor layers (122,126) and an active layer (124), and a reflective layer (132,134) disposed on the second conductive type semiconductor layer (126), wherein one connection electrode (150-1,150-2) connects the first conductive type semiconductor layer (122) of one of the adjacent light emitting cells (P2,P3) to the reflective layer (134) of the other of the adjacent light emitting cells (P1,P2), and wherein in each light emitting cell (P1,P2,P3) a first width (W1) of the second conductive type semiconductor layer (126) in a first direction (X) is the same as or greater than a third width (W3) of the reflective layer (132,134) in the first direction (X), and the first direction (X) differs from a thickness direction of the light emitting structure (120).