Quantum Dot Light-Emitting Layer Ink-Jet Uniformity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing technologies face challenges in forming a uniform quantum dot light-emitting layer without thickness unevenness and cracking, particularly when using ink-jet application, due to limitations in solvent viscosity and drying unevenness issues known as 'coffee ring' effects.

Innovation Solution

Incorporating nanofibers into the colloidal solution with quantum dots allows for the formation of a light-emitting layer with controlled viscosity, enabling ink-jet application regardless of solvent viscosity and preventing drying unevenness, resulting in a uniform and crack-free quantum dot light-emitting layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a colloidal solution containing quantum dots and solvent is applied by ink-jet, then the quantum dot light-emitting layer can be formed, but drying unevenness (coffee ring) occurs in the droplets after application

Engineering Contradiction:

Improveuniformity of quantum dot light-emitting layerVSAvoiddrying unevenness (coffee ring)

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

Nanofibers are introduced as an intermediary substance between quantum dots and solvent. The nanofibers form a three-dimensional network structure that acts as a mediator to control solvent evaporation and prevent coffee ring effect, while also serving as a scaffold for uniform quantum dot distribution

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite colloidal solution containing quantum dots, nanofibers, and solvent. This composite material combines the light-emitting properties of quantum dots with the structural control and viscosity adjustment capabilities of nanofibers, achieving both functionality and processing performance

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the viscosity of the colloidal solution is adjusted for ink-jet application, then the colloidal solution can be ejected, but the solvent viscosity limits the application process

Engineering Contradiction:

Improveink-jet applicabilityVSAvoidsolvent selection flexibility

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent changes the viscosity parameter of the colloidal solution by adding nanofibers. The nanofibers increase the viscosity to an appropriate range for ink-jet application (5-500 mPa·s) without limiting solvent choice, as the viscosity adjustment is achieved through the nanofiber network rather than solvent properties alone

Inventive Principle:

Principle #35Parameter changes

3Illumination intensity

If quantum dots are dispersed in a colloidal solution for light-emitting layer formation, then the light-emitting properties can be achieved, but thickness unevenness and cracking occur in the formed layer

Engineering Contradiction:

Improvelight-emission characteristicsVSAvoiduniformity of light-emitting layer

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The nanofibers create local structural variations that prevent uniform drying and cracking. The three-dimensional network of nanofibers provides localized support throughout the colloidal solution, ensuring uniform quantum dot distribution and preventing thickness unevenness in the formed light-emitting layer

Inventive Principle:

Principle #3Local quality

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 method ensures a uniform quantum dot light-emitting layer is formed without thickness unevenness and cracking, allowing for effective ink-jet application and maintaining light-emission characteristics.

Implementation Method 1

Methodology Applied

Scientific EffectViscosity adjustment through nanofiber incorporation:

Implementation Method 2

preventing drying unevenness, resulting in a uniform and crack-free quantum dot light-emitting layer

Methodology Applied

Scientific EffectCoffee ring effect prevention through nanofiber network formation: Coffee Ring Effect

Data Source

PatentUS11309509B2Display device and manufacturing method for same

Publication Date: 2022.04.19 SHARP KK

AI summary

A display device is provided with a light-emitting element layer including an anode electrode, a cathode electrode, and a quantum dot light-emitting layer sandwiched between the anode electrode and the cathode electrode, wherein the quantum dot light-emitting layer includes at least quantum dots and nanofibers. A method for manufacturing a display device includes forming a quantum dot light-emitting layer by applying a colloidal solution including at least quantum dots and nanofibers by ink-jet.