Narrow Band Emission Phosphor Films for Mini-LED Color Conversion
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Solution Overview
Problem
Existing methods for applying phosphor materials onto miniaturized LED elements are inadequate, leading to limitations in the full potential of mini-LED and micro-LED technologies due to issues like sedimentation, phase separation, and agglomeration of phosphor particles.
Innovation Solution
A film comprising narrow band emission phosphors with a D50 particle size ranging from 0.1 μm to 15 μm, dispersed within a binder matrix, is developed. This film can be used to create color conversion layers for LEDs, miniLEDs, and microLEDs, utilizing green-emitting U6+-containing or Mn2+-containing phosphors, and red-emitting phosphors based on complex fluoride materials activated by Mn4+.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If phosphor materials with small particle sizes are used for mini-LED and micro-LED applications, then the color quality and efficiency are improved, but the materials tend to agglomerate when mixed with commonly used solvents
Solution Approach 1:
The patent introduces a surface-modified phosphor material where phosphor particles are coated with a bifunctional molecule consisting of a phosphor-reactive group and a ligand. This intermediary coating prevents direct interaction between phosphor particles and solvents that would cause agglomeration, while maintaining the small particle size needed for mini-LED and micro-LED applications. The ligand acts as a mediator that provides steric or electrostatic stabilization in the solvent medium.
Solution Approach 2:
The patent modifies the surface properties of phosphor particles by changing their chemical composition through surface modification. By introducing surface-functionalized phosphors with controlled surface chemistry, the patent alters the interaction parameters between phosphor particles and solvents, preventing agglomeration while maintaining the desired particle size for high-color-quality lighting applications.
2Ease of manufacture
If phosphor materials are used in ink jet printable formulations, then the application process is simplified, but the materials suffer from sedimentation and phase separation
Solution Approach 1:
The surface-modified phosphor materials serve as intermediaries that are compatible with ink jet printable formulations. The ligand portion of the surface modification provides steric or electrostatic stabilization that prevents sedimentation and phase separation in the ink medium, enabling simplified ink jet printing application while maintaining formulation stability.
Solution Approach 2:
The patent creates a composite structure where phosphor particles are combined with surface-modifying ligands to form a stable dispersion in ink jet formulations. This composite approach integrates the optical properties of phosphor materials with the stability and processability requirements of ink jet printable materials, achieving both ease of manufacture and formulation stability.
3Use of energy by moving object
If quantum dot materials are used in ink formulations, then the absorption coefficient is strong, but the quantum efficiency is low and thermal stability is poor
Solution Approach 1:
The patent extracts and adopts the advantageous property of quantum dots (strong absorption coefficient) while discarding their disadvantages (low quantum efficiency and poor thermal stability) by using conventional phosphor materials instead. The invention takes out only the beneficial optical absorption characteristic while replacing the problematic quantum dot material with more stable phosphor alternatives.
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 proposed solution enables stable and efficient application of phosphor materials, overcoming issues of sedimentation and agglomeration, and achieving high color quality in lighting and display applications by effectively converting blue LED light into desired wavelengths.
Implementation Method 1
Narrow band emission phosphor materials achieve high color quality in lighting and displays based on LEDs
Data Source
AI summary
A color conversion film is provided. The film includes 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. A device is also provided.