Phosphor Assembly Liquid Immersion Cooling and Index Matching
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Solution Overview
Problem
Current phosphor assemblies experience significant light losses due to air gaps and refractive index differences between the phosphor element and optical system, leading to inefficiencies in light collection and heat management, particularly under high radiant intensities and temperature conditions.
Innovation Solution
A phosphor assembly with a liquid immersion material between the phosphor element and optical system, where the excess material reduces Fresnel losses, facilitates heat dissipation through convection, and extends the assembly's lifetime by continuous exchange and index matching, thereby improving light collection efficiency and reducing damage from high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If air gap is present between phosphor element and optical system, then device complexity is reduced, but light collection efficiency deteriorates due to Fresnel losses and refractive losses
Solution Approach 1:
An immersion material with refractive index between that of the phosphor element and the optical system is introduced as an intermediary substance. This mediator reduces the refractive index difference at the interfaces, thereby minimizing Fresnel losses and improving light collection efficiency without requiring complex optical design modifications.
Solution Approach 2:
The refractive index parameter of the medium between the phosphor element and optical system is changed from air (n≈1.0) to an immersion material with intermediate refractive index. This parameter change optimizes the optical matching between components, reducing reflection losses and improving overall light transmission efficiency.
2Illumination intensity
If high radiant intensity is used to improve brightness, then illumination intensity is improved, but heat generation increases causing phosphor aging and damage
Solution Approach 1:
A liquid immersion material is introduced into the optical system, which serves dual functions: optical matching to improve light collection and thermal management through convection. The liquid medium can be circulated or allowed to naturally convect, carrying heat away from the phosphor element and reducing thermal degradation.
Solution Approach 2:
The immersion material utilizes phase change or convective flow characteristics to enhance heat dissipation. The liquid medium absorbs heat from the phosphor element through convection, potentially involving phase transitions or natural circulation patterns that efficiently transport thermal energy away from the high-intensity radiation zone.
3Temperature
If excess immersion material is provided to enable continuous exchange for cooling, then heat dissipation is improved, but device complexity increases due to fluid management requirements
Solution Approach 1:
The immersion material is provided in excess to enable self-cooling through natural convection. The system utilizes the inherent buoyancy-driven flow of the liquid medium, where heated regions naturally rise and cooler regions sink, creating continuous circulation without requiring external pumps or complex fluid management mechanisms. The excess material ensures sufficient volume for effective convective heat transfer.
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 enhances light collection efficiency by minimizing refractive losses and effectively manages heat, leading to improved performance and extended lifespan of the phosphor assembly under high-intensity conditions.
Implementation Method 1
Fresnel losses, which occur between media having different refractive indices, can be reduced initially. Further, light is refracted away from the optical axis at a transition from a medium having a higher refractive index to air
Implementation Method 2
Fresnel losses, which occur between media having different refractive indices, can be reduced initially
Implementation Method 3
The inventors found that the exchange of immersion material dissipates heat, which can be generated within the phosphor element due to the stokes shift and a possible parasitic absorption of the phosphor
Implementation Method 4
In this way, typically ultra-violet or blue pump light can be converted to light having a longer wavelength by the phosphor (down conversion)
Data Source
AI summary
This invention relates to a phosphor assembly with a phosphor element for converting pump light into converted light, and an optical system for transmitting converted light and/or pump light. Therein, a liquid immersion material is provided in a gap between the phosphor element and the optical system, wherein an excess of immersion material enables a continuous exchange of the material in the gap and thus provides a cooling.