Phosphor Ink Composition for Stable Mini-LED Deposition
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Solution Overview
Problem
Existing methods for applying phosphor materials on miniaturized LEDs face challenges such as sedimentation, phase separation, and agglomeration, which limit the practical application of quantum dots and other phosphors due to low quantum efficiency and poor thermal stability.
Innovation Solution
Development of an ink composition comprising a Mn4+ doped phosphor and a rare earth containing Garnet phosphor, with a particle size of 0.5 to 15 microns, stabilized by metal fluoride coatings and tailored viscosities for precise deposition on mini-LEDs and micro-LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If phosphor materials with small particle sizes are used for mini-LEDs and micro-LEDs, then the LED performance is improved, but the phosphor materials tend to agglomerate when mixed with commonly used solvents
Solution Approach 1:
The patent introduces a specially designed solvent system as an intermediary medium that is compatible with both the small phosphor particles and the LED structure. This solvent acts as a mediator to prevent agglomeration while maintaining particle size benefits, resolving the contradiction between small particle size and dispersion stability.
Solution Approach 2:
The patent changes the chemical and physical parameters of the solvent system to match the surface properties of small phosphor particles. By adjusting solvent polarity, viscosity, and chemical composition, the patent creates a stable dispersion that prevents agglomeration while maintaining the desired small particle size for improved LED performance.
2Illumination intensity
If quantum dot materials are used for ink jet printing, then the color quality is improved, but the quantum efficiency is low and thermal stability is poor
Solution Approach 1:
The patent creates a composite material system combining phosphor particles with a specialized binder matrix that provides both optical performance and thermal stability. This composite structure allows the phosphor to maintain its color quality while the binder system provides thermal stability and prevents degradation, resolving the reliability issues of quantum dot materials.
Solution Approach 2:
The patent employs a sacrificial binder material that can be easily removed or degraded after serving its purpose of holding phosphor particles during processing. This binder is designed to be temporary, providing necessary structural support during manufacturing but being removable to leave only the functional phosphor layer, similar to the disposable nature of quantum dot encapsulation.
3Ease of manufacture
If common organic solvents are used for phosphor dispersions, then the processing is simplified, but sedimentation or phase separation occurs
Solution Approach 1:
The patent fundamentally changes the parameters of the solvent system by transitioning from common organic solvents to a specialized solvent mixture with adjusted polarity, viscosity, and chemical properties. This parameter change creates a solvent system that maintains phosphor particles in stable suspension without causing sedimentation or phase separation, while still being manufacturable.
Solution Approach 2:
The patent introduces a surfactant or stabilizing agent as an intermediary substance in the solvent system. This intermediary component interacts with both the phosphor particles and the solvent to prevent aggregation and phase separation, allowing the use of relatively simple processing methods while maintaining dispersion stability.
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 and efficient deposition of phosphors on mini-LEDs and micro-LEDs, enhancing color quality and stability, suitable for applications in displays and lighting.
Implementation Method 1
The ink composition comprises a phosphor material consisting of a Mn4+ doped phosphor of formula (1) and at least one rare earth containing Garnet phosphor
Data Source
AI summary
Phosphor materials and devices containing such phosphor materials are disclosed. An ink composition of in accordance with the present disclosure comprises a phosphor material comprising a Mn4+ doped phosphor of formula 1, Ax[MFy]:Mn4+ (I), and at least one rare earth containing Garnet phosphor, the at least one rare earth Garnet phosphor is present in the phosphor material in an amount of at least about 80 wt % based on the weight of the phosphor material, where A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MFy] ion; and y is 5, 6 or 7.