Spinel-Bonded Phosphor Plate for Higher Light Extraction
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Solution Overview
Problem
The luminous efficiency of existing phosphor plates with inorganic phosphors dispersed in SiO2-based glass is suboptimal.
Innovation Solution
A phosphor plate comprising a complex of α-sialon phosphor and a sintered body containing spinel, represented by the general formula M2xAl4-4xO6-4x, where M is at least one of Mg, Mn, and Zn, and 0.2<x<0.6, is used in conjunction with a group III nitride semiconductor light emitting element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If inorganic phosphor is dispersed in SiO2-based glass, then the phosphor plate can be manufactured with a simple structure, but the luminous efficiency is insufficient due to light scattering
Solution Approach 1:
The patent changes the material parameter from SiO2-based glass to spinel-based sintered body, which fundamentally alters the optical properties. The spinel structure provides reduced light scattering while maintaining manufacturability through sintering processes, thus resolving the contradiction between manufacturing simplicity and luminous efficiency
Solution Approach 2:
The patent uses a composite structure where α-sialon phosphor particles are dispersed in a spinel sintered body matrix. This composite approach combines the light-emitting properties of α-sialon phosphor with the low scattering properties of spinel, achieving high luminous efficiency while maintaining a relatively simple manufacturing process
2Device complexity
If inorganic phosphor is dispersed in SiO2-based glass, then the phosphor plate structure is simple, but light extraction efficiency is low
Solution Approach 1:
The patent changes the base material parameter from SiO2 glass to spinel sintered body, which has inherently lower light scattering properties. This parameter change improves light extraction efficiency without significantly increasing structural complexity, as the spinel sintered body can be formed using conventional sintering techniques
3Productivity
If the spinel raw material powder has high specific surface area, then the sintering process is faster, but the luminous efficiency decreases due to increased light scattering
Solution Approach 1:
The patent identifies and controls the specific surface area parameter of spinel raw material powder, setting it within the optimal range of 0.1-10.0 m2/g. This parameter optimization balances sintering speed and luminous efficiency, preventing excessive light scattering while maintaining reasonable sintering productivity
Solution Approach 2:
The patent applies different quality requirements to different aspects of the spinel raw material: moderate fineness (specific surface area 0.1-10.0 m2/g) is specified to achieve the right balance between sintering speed and optical properties, rather than using uniformly fine or coarse particles
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 plate achieves excellent luminous efficiency due to reduced light scattering and high light extraction efficiency, resulting in a light emitting device that emits orange color with high brightness.
Implementation Method 1
reduced light scattering and high light extraction efficiency
Implementation Method 2
a phosphor plate including: a complex containing an α-sialon phosphor and a sintered body containing spinel
Data Source
AI summary
A phosphor plate including: a complex containing an α-sialon phosphor and a sintered body containing spinel represented by a general formula M2xAl4-4xO6-4x (where M represents at least one of Mg, Mn, and Zn, and 0.2<x<0.6). In addition, there is provided a light emitting device including: a group III nitride semiconductor light emitting element; and the phosphor plate provided on one surface of the group III nitride semiconductor light emitting element. Further, there is provided a method for manufacturing the phosphor plate.