Flexible Light-Emitting Device With Fiber Electrodes

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Solution Overview

Problem

Conventional electroluminescence elements face challenges in achieving high light extraction efficiency due to the need for high electrical conductivity in electrodes, which reduces light transmittance, and the trade-off between electroluminescence and mechanical light emission performance with the thickness of the light-emitting layer.

Innovation Solution

A flexible light-emitting device utilizing fiber electrodes within a light-emitting complex medium to generate an in-plane electric field, allowing for efficient light emission regardless of the electrode material or light-emitting layer thickness, as the light does not need to pass through the electrodes for extraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the density or thickness of the electrode is increased to improve electrical conductivity, then the electrical conductivity is improved, but the light transmittance of the electrode is lowered, reducing light extraction efficiency

Engineering Contradiction:

Improveelectrical conductivityVSAvoidlight transmittance

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent transitions from planar electrodes to three-dimensional fiber electrodes embedded within the light-emitting layer. This dimensional change allows the electrodes to be distributed throughout the volume of the light-emitting complex medium rather than being confined to surfaces, enabling effective light extraction in multiple directions and eliminating the need for high transmittance in a single electrode plane

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The fiber electrodes are nested within the light-emitting complex medium, with multiple fiber electrodes embedded in the light-emitting layer. This nested structure allows the electrodes to be surrounded by the light-emitting material, enabling light to be extracted through the sides of the fibers rather than requiring the light to pass through the electrode material itself

Inventive Principle:

Principle #7Nested doll (Nesting)

2Power

If the thickness of the light-emitting layer is reduced to apply a strong electric field for electroluminescence, then the electroluminescence performance is improved, but the mechanical light emission performance is reduced

Engineering Contradiction:

Improveelectroluminescence performanceVSAvoidmechanical light emission performance

Core Design Contradiction:

PowerVSIllumination intensity

Solution Approach 1:

The fiber electrodes create electric fields in three-dimensional space around each fiber, rather than requiring a uniformly thin layer. The electric field extends radially from each fiber electrode, allowing effective electroluminescence activation throughout the volume of the light-emitting complex medium regardless of the overall layer thickness

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The light-emitting layer is segmented into multiple regions, each surrounding individual fiber electrodes. This segmentation allows different thickness configurations for different applications, as each fiber electrode independently generates the necessary electric field in its surrounding region, decoupling the overall layer thickness from the electric field strength requirement

Inventive Principle:

Principle #1Segmentation

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 approach enables high-efficiency light emission with fiber electrodes of low light transmittance and maintains performance across varying light-emitting layer thicknesses, improving upon conventional devices by eliminating the need for high transmittance electrodes and optimizing both electroluminescence and mechanical light emission.

Implementation Method 1

a light-emitting complex medium including a polymer matrix, and a nano light-emitting material dispersed therein, the light-emitting complex medium generating light via application of an electric field thereto

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS10794553B1Flexible light-emitting device including conductive fiber

Publication Date: 2020.10.06 DAEGU GYEONGBUK INSTITUTE OF SCIENCE AND TECHNOLOGY

AI summary

Provided is a flexible light-emitting device including: a light-emitting complex medium including a polymer matrix, and a nano light-emitting material dispersed therein, the light-emitting complex medium generating light via application of an electric field thereto; a plurality of first fiber electrodes extending in a first direction and disposed within the light-emitting complex medium, wherein the plurality of first fiber electrodes are arranged along a first imaginary plane and are spaced apart from each other, wherein a first voltage is applied to the plurality of first fiber electrodes; and a plurality of second fiber electrodes extending in the first direction and disposed within the light-emitting complex medium, wherein the plurality of first fiber electrodes are alternated with the plurality of second fiber electrodes, wherein a second voltage different from the first voltage is applied to the plurality of second fiber electrodes.