Beta-Sialon Phosphor Microstrain Control for Emission Stability
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Solution Overview
Problem
Conventional β-type sialon phosphors have inadequate emission characteristics and reliability, particularly in terms of emission efficiency and long-term chromaticity stability in light-emitting devices.
Innovation Solution
A β-type sialon phosphor with specific microstrain calculated by the Halder-Wagner method, having a crystal phase represented by the formula Eu_aSi_bAl_cOdNe, with microstrain of 0.049% or less, crystallite size of 100 nm or larger, and an emission peak in the 500 nm to 560 nm range when excited with light of 300 nm to 500 nm, providing improved reliability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional β-type sialon phosphors are used, then the phosphor can be easily manufactured, but the emission efficiency and long-term chromaticity stability are inadequate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the microstrain of the β-type sialon phosphor crystal lattice to 0.049% or less and the crystallite size to 100 nm or more. This specific parameter control resolves the contradiction by achieving high emission efficiency and chromaticity stability through microstrain reduction, while maintaining compatibility with existing manufacturing processes that can produce such crystallite sizes.
Solution Approach 2:
The patent employs composite material principles by creating a β-type sialon phosphor with specific compositional ratios (Si: 3.0-5.6, Al: 0.006-3.0, O: 0.006-2.0, N: 7.0-8.0) combined with controlled microstrain and crystallite size. This composite approach optimizes both emission characteristics and manufacturing feasibility by balancing multiple compositional and structural parameters.
2Reliability
If the microstrain is reduced to improve emission characteristics, then the emission efficiency improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent transforms the manufacturing challenge by establishing clear quantitative thresholds (microstrain ≤ 0.049%, crystallite size ≥ 100 nm) that guide the sintering process. These parameter specifications enable manufacturers to achieve high emission efficiency through controlled heating treatments without requiring excessive precision, as the thresholds provide clear targets for process optimization.
3Reliability
If the crystallite size is increased to improve emission characteristics, then the emission efficiency improves, but the manufacturing complexity increases
Solution Approach 1:
The patent simplifies manufacturing by specifying a clear crystallite size threshold (≥ 100 nm) that can be achieved through conventional sintering processes. This parameter specification avoids the need for complex nanotechnology or advanced materials processing, allowing manufacturers to produce high-performance phosphors using established ceramic sintering techniques with controlled heating and cooling cycles.
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 phosphor achieves excellent emission characteristics and high reliability in light-emitting devices, enhancing emission efficiency and maintaining stable emission properties over long-term use.
Implementation Method 1
exhibiting an emission peak in a wavelength range of 500 nm or more to 560 nm or less when irradiated with an excitation light having a wavelength of 300 nm or more to 500 nm or less
Data Source
AI summary
Provided is a phosphor that includes a crystal phase represented by the following Formula [1] and has a microstrain of 0.049% or less as calculated by the Halder-Wagner method: EuaSibAlcOdNe [1] (wherein, a, b, c, d, and e represent values satisfying the following respective ranges: 0<a≤0.2, 5.6<b≤5.994, 0.006≤c<0.4, b+c=6, 0.006≤d<0.4, and 7.6<e≤7.994).