High Refractive Index Copolymer for OLED Light Extraction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current materials for electronic and display applications face challenges in achieving high refractive indices while maintaining processability and optical efficiency, leading to inefficiencies in light management and increased power consumption in devices like LEDs and OLEDs.

Innovation Solution

A copolymer composition comprising bifunctional high refractive index monomers with UV- or thermally-reactive groups, capable of increasing solubility in aqueous media, and additional monomers with nucleophilic reactive groups, formulated to achieve a refractive index greater than 1.620 at 550 nm and high transmittance, enabling photopatternability and efficient light management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional polymeric materials are used in optical devices, then processability and chemical resistance are improved, but light extraction efficiency deteriorates due to refractive index mismatch

Engineering Contradiction:

ImproveprocessabilityVSAvoidlight extraction efficiency

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent modifies the refractive index parameter of polymeric materials by incorporating high refractive index components (metal oxides, heteroatom-containing groups) into the polymer structure, changing the optical properties while maintaining the polymeric nature and processability of the material

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates composite polymeric materials by combining conventional polymer matrices with high refractive index additives such as metal oxides (TiO2, ZnO, SiO2) or incorporating heteroatom-containing functional groups, achieving both high refractive index and polymeric processability

Inventive Principle:

Principle #40Composite materials

2Illumination intensity

If display brightness is increased to compensate for light loss, then visibility is improved, but power consumption increases

Engineering Contradiction:

Improvedisplay brightnessVSAvoidpower consumption

Core Design Contradiction:

Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent converts the harmful effect of refractive index mismatch (which causes light loss) into a beneficial effect by designing materials with matched refractive indices across device layers, turning the optical interface from a source of loss into an efficient light transmission pathway

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Loss of energy

If high refractive index materials are used to improve light extraction, then brightness efficiency is improved, but material processability and solubility deteriorate

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidmaterial processability

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent changes the solubility and processing parameters of high refractive index materials by developing aqueous-based formulations and adjusting molecular weight and functional group composition, enabling processing of high refractive index materials using conventional aqueous techniques

Inventive Principle:

Principle #35Parameter changes

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 copolymer composition enhances light extraction and brightness in displays, reduces power consumption, and facilitates the use of smaller optical elements, addressing inefficiencies in existing materials by providing improved refractive index and processability.

Implementation Method 1

Many such devices can exhibit significant losses in efficiency because of the way that light moves within and through their structural elements... a significant percentage of the generated light is lost via internal reflection and waveguiding as it passes between elements or layers of different refractive indices

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

The copolymer composition enhances light extraction and brightness in displays... photopatternability and efficient light management

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS20240152047A1High refractive index materials

Publication Date: 2024.05.09 DUPONT ELECTRONIC MATERIALS INT LLC

AI summary

Disclosed is a formulation comprising a copolymer comprising one or more bifunctional high refractive index first monomers comprising a high refractive index aromatic core and further comprising one or more UV- or thermally-reactive groups (A) and one or more second monomers comprising a high refractive index core and further comprising one or more groups capable of reacting to increase the solubility of the copolymer in aqueous media (B), and one or more solvents. The formulation may optionally contain additional components. Further disclosed are methods for forming optical thin films from the formulation and optical devices containing the optical thin films.