CaAlSiN3 Eu Phosphor Luminous Efficiency
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Solution Overview
Problem
Existing red phosphors, such as CaAlSiN3 activated with Eu2+, face challenges in achieving high luminous efficiency due to variations in composition and lattice constants, leading to decreased fluorescence intensity and generation of heterogeneous phases.
Innovation Solution
A specific compositional range of CaAlSiN3 activated with Eu2+, represented by the formula Cax+yEuySiAlN3, where x+y is between 1.0 and 1.1, y is between 0.004 and 0.012, and with specific lattice constants and element content ranges, ensures higher luminous efficiency by maintaining electric neutrality and optimizing fluorescence characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the composition of CaAlSiN3 is varied to improve luminous efficiency, then fluorescence intensity increases, but heterogeneous phases are generated and crystal structure stability deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional parameters (x and y in Cax+yEuySiAlN3) and lattice constant parameters (a and c) to optimize luminous efficiency while maintaining crystal structure stability. The specific ranges of x+y (1.0-1.1) and y (0.004-0.012) represent controlled parameter variations that improve performance without causing heterogeneous phase formation.
Solution Approach 2:
The patent applies local quality by introducing Eu2+ dopants at specific local concentrations (y parameter) within the CaAlSiN3 crystal lattice. This localized doping strategy allows optimization of fluorescence properties at specific sites while maintaining the overall stability of the host crystal structure.
2Illumination intensity
If Eu2+ content is increased to enhance fluorescence intensity, then luminous efficiency improves, but composition control becomes more difficult and heterogeneous phases form
Solution Approach 1:
The patent uses parameter changes by defining specific ranges for Eu content (y = 0.004-0.012) and total cation content (x+y = 1.0-1.1), which provides clear manufacturing targets that balance fluorescence enhancement with compositional control. These parameter specifications prevent heterogeneous phase formation while maximizing luminous efficiency.
Solution Approach 2:
The patent applies partial action by using small, controlled amounts of Eu2+ dopant (y = 0.004-0.012) rather than large concentrations. This partial doping approach is sufficient to achieve high fluorescence intensity while avoiding the formation of heterogeneous phases that would result from excessive Eu content.
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 specified composition and lattice constants in the phosphor Cax+yEuySiAlN3 result in higher luminous efficiency, with improved fluorescence intensity and reduced heterogeneous phase generation, enhancing the performance of light emitting elements and devices.
Implementation Method 1
a phosphor represented by the general formula: Cax+yEuySiAlN3... activated with Eu, and some of the Ca element(s) being substituted with the Eu element(s)... a light emitting element comprising the phosphor and a light source configured to irradiate the phosphor with excitation light
Data Source
AI summary
An object of the present invention is to provide a red phosphor, a light emitting element using the phosphor, and a light emitting device using the light emitting element. A phosphor represented by the general formula: Cax+yEuySiAlN3 in which x+y is 1.0 or more and 1.1 or less, y is 0.004 or more and 0.012 or less, the phosphor being activated with Eu, and some of the Ca element(s) being substituted with the Eu element(s), wherein the phosphor has a lattice constant a of 0.9747 nm or more and 0.9770 nm or less, and a lattice constant c of 0.5050 nm or more and 0.5055 nm or less, and wherein the phosphor has a Ca content of 27.8% by mass or more and 28.8% by mass or less, a dissolved oxygen content in the phosphor of 0.3% by mass or more and 1.2% by mass or less, and an Eu content of 0.4% by mass or more and 1.2% by mass or less.