Porous Optoceramic Converter for Blue Light Scattering
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Solution Overview
Problem
Ceramic converter materials used in optoelectronic devices for transmission applications are not suitable for remission converters due to different requirements, leading to inefficient light scattering and reduced luminous flux.
Innovation Solution
A single-phase porous optoceramic material with a composition of A3B5O12, doped with cerium and other activating elements, is developed to achieve strong light scattering and high quantum efficiency, allowing for optimal optical and mechanical properties suitable for remission converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If transmission converter configuration is used with ceramic converter materials, then the converted light can be transmitted through the converter, but the blue excitation light is not sufficiently scattered leading to poor color mixing
Solution Approach 1:
The patent employs a porous ceramic converter material with controlled pore sizes (0.5-5 μm) and porosity (5-20%) to scatter blue excitation light. The pores act as scattering centers that diffuse the incident blue light throughout the converter material, enabling effective color mixing with the converted yellow light in transmission configuration, while maintaining mechanical integrity and thermal conductivity.
2Illumination intensity
If scattering is increased by incorporating pores or second phases, then blue light scattering improves, but remission of blue excitation light increases reducing luminous flux efficiency
Solution Approach 1:
The patent optimizes the pore size parameter to 0.5-5 μm and porosity to 5-20%, creating a balance where sufficient scattering occurs to mix colors effectively while minimizing remission losses. The pore dimensions are specifically tuned to scatter blue light (430-480 nm) effectively while allowing the converted yellow light (560-580 nm) to pass through with minimal loss, thereby maintaining high luminous flux efficiency.
Solution Approach 2:
The patent uses a composite ceramic structure combining a transparent ceramic matrix (such as Y3Al5O12:Ce) with controlled porosity. This composite structure provides both the optical clarity needed for light transmission and the scattering centers (pores) needed for color mixing, while the ceramic matrix maintains mechanical strength and thermal conductivity that would be lost with excessive porosity.
3Strength
If ceramic converter material density is increased to 97% or higher, then mechanical stability improves, but light scattering capability decreases
Solution Approach 1:
The patent deliberately introduces controlled porosity (5-20%) into the ceramic converter material, creating a porous structure that maintains adequate mechanical stability while providing numerous scattering centers for effective blue light scattering. The pore distribution and size are optimized to ensure sufficient scattering without compromising the structural integrity required for practical converter applications.
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 material effectively converts excitation light into emitted light with high remission efficiency, achieving a homogeneous color impression and increased efficiency in applications like projectors, while maintaining mechanical stability and thermal conductivity.
Implementation Method 1
the blue excitation light is scattered by the ceramic converter material
Implementation Method 2
the converter material converts irradiated excitation light having a first wavelength (also referred to as blue excitation light below) at least partially to emit light having a second wavelength
Data Source
AI summary
A strongly scattering optoceramic converter material having a density of less than 97% is provided, as well as a method for producing such an optoceramic material. By appropriately choosing in particular the composition, blending method, and sintering conditions, the production method permits to produce converter materials with tailored properties.