Patterned Phosphor Structures for High-Resolution Micro-LED Color Conversion
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Solution Overview
Problem
Existing methods for applying phosphor materials to miniaturized LEDs, such as mini-LEDs and micro-LEDs, face challenges due to low quantum efficiency, poor thermal stability, sedimentation, and agglomeration of quantum dots, and limitations in ink-jet printing resolution and formulation requirements, hindering the development of high-resolution color conversion elements for displays.
Innovation Solution
Development of Mn4+ doped phosphors with complex fluoride materials and specific particle sizes, combined with binders and solvents, to create stable ink compositions that can be deposited using methods like ink-jet printing, enabling patterned films with features smaller than 250 microns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If quantum dot materials are used for ink jet printing, then color quality is improved, but quantum efficiency is low and thermal stability is poor
Solution Approach 1:
The patent changes the material parameters from quantum dots to phosphor materials with specific particle size ranges (D10: 0.1-1.0 μm, D50: 1.0-5.0 μm, D90: 5.0-20.0 μm) and specific compositional parameters (host material ratios, dopant concentrations) to achieve both high color quality and improved quantum efficiency and thermal stability
Solution Approach 2:
The patent uses composite phosphor materials consisting of host materials (e.g., YAG, LuAG, GAG) doped with activator ions (e.g., Ce3+, Eu2+, Mn4+), combining multiple materials to achieve superior color quality, quantum efficiency, and thermal stability compared to single-material quantum dots
2Stability of the object's composition
If phosphor materials with small particle sizes are used, then coating stability is improved, but agglomeration occurs when mixed with common solvents
Solution Approach 1:
The patent introduces dispersant materials as intermediaries between phosphor particles and solvents. These dispersants have specific chemical structures that adsorb onto phosphor surfaces, providing steric or electrostatic repulsion to prevent agglomeration while maintaining stable dispersion in common solvents
Solution Approach 2:
The patent optimizes particle size parameters (D10: 0.1-1.0 μm, D50: 1.0-5.0 μm, D90: 5.0-20.0 μm) to a specific range that balances stable dispersion with reduced agglomeration tendency, and adjusts compositional parameters including dispersant concentration and phosphor composition to prevent harmful interactions
3Manufacturing precision
If ink jet printing is used for delivering color conversion materials, then spatial resolution is improved, but achievable resolution is limited to about 40 microns and formulation requirements are stringent
Solution Approach 1:
The patent changes the particle size parameters of phosphor materials to a specific range (D10: 0.1-1.0 μm, D50: 1.0-5.0 μm, D90: 5.0-20.0 μm) that is smaller than the ink jet printing resolution limit, enabling the ink jet process to resolve individual particle distributions and achieve feature sizes below 40 microns. The patent also adjusts formulation parameters including viscosity, surface tension, and solvent composition to reduce stringent formulation requirements
Solution Approach 2:
The patent uses photolithography as a copying method to transfer patterns onto substrates with resolutions below 40 microns, then uses this patterned substrate as a template for subsequent phosphor deposition, effectively bypassing the resolution limitations of direct ink jet printing
4Illumination intensity
If phosphor materials are used for mini-LED and micro-LED applications, then color quality is improved, but particle size must be correspondingly small which causes agglomeration
Solution Approach 1:
The patent changes the particle size parameters to a specific range (D10: 0.1-1.0 μm, D50: 1.0-5.0 μm, D90: 5.0-20.0 μm) that is small enough for mini-LED and micro-LED applications while being optimized to prevent agglomeration through controlled surface properties and dispersant selection
Solution Approach 2:
The patent introduces surface treatment agents and dispersants as intermediaries that coat the phosphor particle surfaces, preventing direct particle-to-particle contact and agglomeration while maintaining the small particle size required for mini-LED and micro-LED color conversion applications
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 high color quality lighting and displays with improved quantum efficiency, thermal stability, and reduced agglomeration, allowing for precise deposition of phosphors on mini-LEDs and micro-LEDs, enhancing display resolution and reliability.
Implementation Method 1
Narrow band emission phosphor materials achieve high color quality in lighting and displays based on LEDs
Implementation Method 2
Ink jet printable ink has been prepared using quantum dots
Data Source
AI summary
Optically active devices and processes for preparing such devices are disclosed. A device in accordance with the present disclosure comprises a patterned surface, wherein the patterned surface comprises a plurality of pattern elements, and a plurality of LED light sources each optically coupled and/or radiationally connected to at least one pattern element of the plurality of pattern elements. The plurality of pattern elements comprise at least one optically active material and a photoresist material.