Phosphor Surface Nanostructures for Light Transmission
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Solution Overview
Problem
Phosphor elements in wavelength conversion systems face optical losses due to phosphor quenching and poor anti-reflection coating adhesion on porous, soft, and rough surfaces, limiting phosphorescence intensity and uniformity.
Innovation Solution
Engineered conical surface nanostructures with lateral dimensions less than the wavelength of phosphorescence light are integrated into the phosphor element, providing a gradual refractive index transition from the phosphor material to air, enhancing light transmission and eliminating adhesion issues with anti-reflection coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If anti-reflection coating is applied to phosphor element surface, then light transmission is improved, but coating adhesion deteriorates due to porous and rough surface
Solution Approach 1:
The patent applies anti-reflection coating to the phosphor element surface before the phosphor material is applied. This preliminary coating application ensures that the coating adheres to the solid phosphor element surface rather than attempting to adhere to the porous and rough phosphor particles, thereby maintaining both light transmission benefits and coating adhesion reliability
Solution Approach 2:
The patent separates the anti-reflection coating function from the phosphor material application process. By applying the coating to the phosphor element surface first and then applying the phosphor material, the system divides the functions into distinct steps, avoiding the adhesion problem that would occur if coating were applied directly to porous phosphor particles
2Illumination intensity
If pump beam power is increased to compensate for reflection losses, then light output is improved, but phosphor quenching worsens due to heating effects
Solution Approach 1:
The patent converts the harmful effect of pump beam reflection into a beneficial outcome by applying anti-reflection coating. Instead of increasing pump power to compensate for reflection losses (which would cause phosphor quenching), the coating reduces reflection losses directly, allowing the system to maintain or improve phosphorescence output without increasing heating and thus avoiding phosphor quenching
3Strength
If phosphor element surface is made rough for better phosphor particle adhesion, then particle attachment is improved, but light transmission deteriorates
Solution Approach 1:
The patent applies anti-reflection coating to the phosphor element surface before applying phosphor particles. This preliminary coating creates a smooth, optically optimized surface that maintains light transmission while still allowing phosphor particles to adhere effectively, thus resolving the contradiction between surface roughness for adhesion and smoothness for light transmission
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 surface nanostructures reduce phosphorescence reflection losses, increase phosphorescence transmission over a broader bandwidth, and improve light coupling efficiency, overcoming the limitations of phosphor quenching and coating adhesion problems.
Implementation Method 1
providing a gradual refractive index transition from the phosphor material to air, enhancing light transmission
Implementation Method 2
Phosphor elements are known for converting light wavelength, usually down-converting from a shorter wavelength to one or more longer wavelengths
Data Source
AI summary
Phosphor elements comprising phosphors in a host material having a phosphorescence-emitting surface with surface nanostructures are disclosed. Phosphor wheels having such phosphor elements, methods of making such phosphor elements, and methods of using such phosphor elements are also disclosed.