Oxynitride Phosphor Composition for High Luminance
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Solution Overview
Problem
Conventional oxynitride phosphors have low light emission efficiency, limiting their ability to achieve high luminance and color rendering in light emitting devices, despite efforts to improve their composition and crystallinity.
Innovation Solution
A complex oxynitride phosphor with a specific composition ratio, represented by the formula M1aM2bRecSidOeNf, where M1 includes Y, Sc, or Al, M2 includes Zn, Sr, Ba, or Ca, and Re includes Ce, Eu, or other rare-earth and transition metal elements, with optimized molar ratios to enhance light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional oxynitride phosphors are used with standard composition ratios, then the phosphor structure is simple and easy to manufacture, but the light emission efficiency is low
Solution Approach 1:
The patent applies parameter changes by optimizing the composition ratios of elements in the oxynitride phosphor. Specifically, it controls the molar ratios of Si, N, O, and rare-earth metal elements within specific ranges to achieve maximum light emission efficiency. This compositional optimization allows the phosphor to convert more excitation energy into visible light, directly addressing the low light emission efficiency problem while maintaining manufacturability through conventional ceramic processing techniques.
Solution Approach 2:
The patent employs composite materials by creating a multi-element oxynitride phosphor system that combines silicon nitride base structure with oxygen substitution and rare-earth metal doping. This composite approach integrates multiple functional components: the Si-N-O framework provides structural stability and optical properties, while rare-earth metals (such as Eu, Ce, Pr) serve as luminescent centers. The synergistic combination of these elements achieves high light emission efficiency that cannot be obtained with single-element phosphors.
2Loss of energy
If the composition of oxynitride phosphors is optimized for higher light emission efficiency, then the light emission efficiency improves, but the composition control becomes more complex
Solution Approach 1:
The patent systematically optimizes multiple compositional parameters simultaneously: the Si:N:O ratio, the concentration of rare-earth metal elements, and the overall stoichiometry. By establishing specific numerical ranges for each parameter (e.g., O content at 0.1-0.5 per Si atom, rare-earth metal at 0.01-0.1 per formula unit), the patent transforms the complex composition control into a set of manageable specifications that can be implemented using standard ceramic processing while achieving superior light emission efficiency.
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 higher light emission efficiency and luminance by controlling the composition ratio, resulting in a stable crystal structure and reduced absorption, leading to improved light extraction efficiency and high luminance in light emitting devices.
Implementation Method 1
a complex oxynitride phosphor which is efficiently excited in the UV to near-UV wavelength region and emits green to yellow light
Data Source
AI summary
The present invention relates to a complex oxynitride phosphor which is efficiently excited in the UV to near-UV wavelength region and emits green to yellow light, and a light emitting device using the phosphor. The phosphor according to the present invention is characterized in that it is represented by general formula: M1aM2bRecSidOeNf; wherein M1 is one or more elements selected from Y, Sc, La, and Al; M2 is one or more elements selected from Zn, Sr, Ba, Ca, and Mg; Re is one or more elements selected from Ce, Pr, Sm, Eu, Dy, Ho, Er, Tm, Yb, Ti, Cr, and Mn among rare-earth elements and transition metal elements; and a, b, c, d, e, and fin the formula satisfy the relationships:a+b+c=1,0.20<b<0.50,0.001<c<0.10,2.5<d<4.1,0.5<e<1.0, and3.5<f<5.6.