Phosphor Ceramic Pore Control for Light Emitting Devices
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Solution Overview
Problem
Existing phosphor ceramics face challenges in maintaining pore size stability during high-temperature sintering, leading to poor productivity and inadequate transmittance and scattering properties, along with issues like speckle noise in light-emitting devices.
Innovation Solution
A phosphor ceramic with pores of 3.0 µm to 12.0 µm diameter and specific volume percentages, combined with controlled impurity levels, is used to enhance transmittance and scattering properties, and reduce speckle noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pores with pore diameter on the order of nanometers are produced to improve transmittance in wider viewing angle, then transmittance is improved, but adjustment of pore size is difficult and productivity is poor
Solution Approach 1:
The patent changes the pore diameter parameter from nanometer scale (250-2900 nm) to micrometer scale (3.0-12.0 μm). This parameter change makes pore size adjustment easier and improves productivity while maintaining good transmittance properties, resolving the contradiction between transmittance improvement and productivity enhancement
2Reliability
If high temperature sintering is performed to produce ceramic conversion element, then ceramic material is formed, but pores with pore diameter on the order of nanometers disappear
Solution Approach 1:
The patent changes the pore diameter parameter to micrometer scale (3.0-12.0 μm), which is stable during high-temperature sintering. The pore volume percentage is controlled within 1.5-9.5%, ensuring pore structure stability while maintaining ceramic material formation, thus resolving the contradiction between ceramic formation and pore size stability
3Ease of manufacture
If conventional phosphor ceramic is used, then basic light conversion is achieved, but speckle noise occurs giving unnatural glaring
Solution Approach 1:
The patent changes the pore diameter parameter to micrometer scale (3.0-12.0 μm) and controls pore volume percentage (1.5-9.5%). This parameter change reduces speckle noise and unnatural glaring while maintaining light conversion function, resolving the contradiction between ease of manufacture and reduction of harmful optical effects
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 solution results in improved transmittance, scattering properties, and reduced speckle noise, while also increasing productivity and reducing production costs in light-emitting devices.
Implementation Method 1
a phosphor layer that is capable of converting the blue light to yellow light
Implementation Method 2
improves transmittance in a wider viewing angle
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3A~3C
AI summary
The phosphor ceramic has pores with a pore diameter of 3.0 µm or more and 12.0 µm or less. In the phosphor ceramic, a pore volume percentage of pores with a pore diameter of 3.0 µm or more and 12.0 µm or less is 1.5% by volume or more and 9.5% by volume or less.