Fluoride Fluorescent Material Mn4+ Doping for High Luminance
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Solution Overview
Problem
Conventional fluoride fluorescent materials used in light emitting devices do not achieve satisfactory light emission intensity, particularly in red light-emitting applications, which is crucial for display and lighting applications requiring high luminance and color reproduction.
Innovation Solution
A fluoride fluorescent material with a chemical composition represented by K2[M1−aMn4+aF6], where M is an element from Groups 4 and 14 of the Periodic Table, and a satisfies 0<a<0.2, with a weight median diameter of 30 μm or more, and a bulk density of 0.80 g/cm3 or more, is developed. This material is produced by mixing solutions containing tetravalent manganese ions, potassium ions, and elements from Groups 4 and 14, and is used in conjunction with a light source emitting light in the range of 380 to 485 nm to enhance light emission intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional fluoride fluorescent materials are used, then the material structure is simple and easy to manufacture, but the light emission intensity is insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the doping concentration of Mn4+ ions (parameter a in the formula K2[M1−aMn4+aF6] where 0 < a ≤ 0.2) and adjusting the weight median diameter (30 μm or more) and bulk density (0.80 g/cm3 or more) of the fluorescent material particles. These parameter optimizations resolve the contradiction by achieving high light emission intensity through controlled compositional parameters while maintaining a relatively simple fluoride crystal structure based on K2MF6.
Solution Approach 2:
The patent employs composite materials by creating a doped fluorescent material with the chemical formula K2[M1−aMn4+aF6], where M represents elements from Groups 4 and 14 of the periodic table (such as Ti, Zr, Hf, Si, Ge, or Sn). This composite structure combines the host fluoride crystal lattice with Mn4+ activator ions, achieving enhanced light emission intensity through the synergistic effect of the host-guest system while maintaining structural simplicity.
2Manufacturing precision
If the fluorescent material is optimized for narrow half band width emission, then color reproduction improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent achieves narrow half band width emission (excellent color purity) by precisely controlling the Mn4+ doping parameter a (where 0 < a ≤ 0.2) in the formula K2[M1−aMn4+aF6]. This parameter optimization ensures that the emission spectrum maintains a narrow half band width, providing excellent color reproduction while using a relatively simple single-phase fluoride crystal structure that is easier to manufacture compared to multi-phase composite 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 developed fluoride fluorescent material exhibits a narrow half band width emission peak and achieves excellent light emission intensity, making it suitable for display applications, particularly in liquid crystal displays, with improved luminance and color reproduction capabilities.
Implementation Method 1
A light emitting device emitting a light of a white color or the like is controlled in color tone by the principle of mixing colors of lights... a system using a light emitting element emitting a blue light and a fluorescent material emitting, e.g., a yellow light have been well known
Data Source
AI summary
The present invention provides a method for producing a fluoride fluorescent material comprising a chemical composition represented by the following formula (I):K2[M1−aMn4+aF6] (I)wherein M is at least one element selected from the group consisting of elements belonging to Groups 4 and 14 of the Periodic Table, and a is a value that satisfies the relationship: 0<a<0.2, and a minimum value of a weight median diameter of the fluoride fluorescent material is greater than or equal to 30 μm. The method comprises mixing together a first solution containing at least first complex ions comprising tetravalent manganese and hydrogen fluoride, a second solution containing at least potassium ions and hydrogen fluoride and a third solution containing at least second complex ions comprising at least one element selected from the group consisting of elements belonging to Groups 4 and 14 of the Periodic Table and fluorine ions.