Narrow-Band Phosphor Ink Films for Stable Mini-LED Color Conversion

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Solution Overview

Problem

Current methods for applying phosphor materials on miniaturized LEDs face challenges due to low quantum efficiency, poor thermal stability, and agglomeration issues with quantum dots, and sedimentation problems with organic solvents, which hinder the full potential of mini-LED and micro-LED technologies.

Innovation Solution

Development of an ink composition with a binder material and uniformly dispersed narrow band emission phosphors, specifically green-emitting U6+ and Mn2+ containing phosphors, and red-emitting phosphors based on complex fluoride materials activated by Mn4+, with particle sizes between 0.1 µm to 15 µm, suitable for inkjet printing and coating processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If quantum dot materials are used for ink jet printable ink, then strong absorption coefficient is achieved, but low quantum efficiency and poor thermal stability occur

Engineering Contradiction:
Improveabsorption coefficientVSAvoidquantum efficiency and thermal stability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent changes the material parameters from quantum dots to phosphor materials with optimized particle size (0.1-15 µm) and composition (U6+ green-emitting phosphors and Mn4+ red-emitting phosphors), achieving both strong absorption and high quantum efficiency while improving thermal stability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite phosphor materials combining U6+ green-emitting phosphors and Mn4+ red-emitting phosphors in a binder matrix, creating a composite system that achieves superior absorption, quantum efficiency, and thermal stability compared to single-material systems

Inventive Principle:
Principle #40Composite materials

2Length of moving object

If phosphor materials with small particle sizes are used, then coating and printing processes are enabled, but agglomeration occurs when mixed with commonly used solvents

Engineering Contradiction:
Improveparticle sizeVSAvoiddispersion stability
Core Design Contradiction:
Length of moving objectVSStability of the object's composition

Solution Approach 1:

The patent introduces a binder material as an intermediary between the phosphor particles and solvents, creating a stable suspension system where the binder prevents phosphor agglomeration while maintaining compatibility with ink jet printing and coating processes

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes particle size parameters to 0.1-15 µm range and controls particle size distribution, enabling small enough particles for mini-LED and micro-LED applications while preventing excessive agglomeration through proper size control and binder selection

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If phosphor materials are used with commonly used organic solvents, then dispersion is achieved, but sedimentation or phase separation occurs

Engineering Contradiction:
ImprovedispersionVSAvoidsedimentation resistance
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The binder material serves as a mediator between phosphor particles and organic solvents, creating a stable colloidal suspension that prevents sedimentation and phase separation while maintaining good dispersion for coating and printing applications

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite ink formulation combining phosphor materials, binder, and organic solvents in optimized ratios, forming a stable composite system that maintains dispersion stability and prevents sedimentation during storage and application

Inventive Principle:
Principle #40Composite materials

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 solution provides stable dispersions, prevents agglomeration, and enhances color conversion efficiency in lighting and display applications, achieving high color quality and improved thermal stability for mini-LED and micro-LED technologies.

Implementation Method 1

Narrow band emission phosphor materials achieve high color quality in lighting and displays based on LEDs

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 2

at least one narrow band emission phosphor being uniformly dispersed throughout the composition

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentEP4410911A1Ink compositions and films with narrow band emission phosphor materials
Publication Date: 2024.08.07 GE INTELLECTUAL PROPERTY LICENSING LLC
  • EP4410911A1 patent drawingFigure 1A~1B
  • EP4410911A1 patent drawingFigure 2~3
  • EP4410911A1 patent drawingFigure 4~5

AI summary

The invention relates to a film comprising at least one narrow band emission phosphor dispersed within a binder matrix, wherein the narrow band emission phosphor has a D50 particle size from about 0.1 µm to about 15 µm and is selected from the group consisting of a green-emitting U6+-containing phosphor, a green-emitting Mn2+-containing phosphor, a red-emitting phosphor based on complex fluoride materials activated by Mn4+, and a mixture thereof.