Segmented Phosphor Wheel for Illumination Efficiency
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Solution Overview
Problem
Illumination devices with phosphor wheels face efficiency losses due to uniform pump light distribution across phosphors, which leads to suboptimal conversion efficiency and geometrical efficiency, especially at high pump power densities, as different phosphors have varying quenching properties requiring tailored pump light distributions.
Innovation Solution
A phosphor wheel with multiple phosphor regions arranged in different planes to receive varying pump light distributions, allowing for customized intensity exposure and reduced local heating, combined with an optical configuration that adjusts pump light focus and collection to optimize conversion efficiency and reduce quenching effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform pump light distribution is used across all phosphors, then the system structure is simple, but the conversion efficiency decreases due to mismatched quenching properties of different phosphors
Solution Approach 1:
The patent applies local quality by creating non-uniform pump light distribution across different phosphor regions. Specifically, the pump light intensity is tailored to match the quenching properties of each phosphor material, with higher intensity for phosphors with strong quenching and lower intensity for those with weak quenching. This localized optimization of pump light parameters maximizes overall conversion efficiency while accounting for material-specific characteristics.
Solution Approach 2:
The patent implements parameter changes by varying the pump light intensity distribution across the phosphor wheel. The system dynamically adjusts the pump light parameters (intensity, distribution pattern) to optimize excitation for different phosphor regions. This parameter optimization resolves the contradiction by enabling high conversion efficiency without requiring structural complexity in the pump light source itself.
2Productivity
If high pump light intensity is used to increase conversion efficiency, then more conversion light is produced, but phosphor quenching increases and efficiency decreases
Solution Approach 1:
The patent applies local quality by matching pump light intensity to the specific quenching characteristics of each phosphor region. Phosphors with strong quenching properties receive optimized intensity levels that prevent excessive heating and efficiency loss, while phosphors with weak quenching can handle higher intensities. This localized intensity optimization maximizes conversion light output while minimizing quenching-related energy losses.
Solution Approach 2:
The patent employs partial action by applying different levels of pump light intensity to different phosphor regions rather than uniform high intensity across all phosphors. This partial optimization approach prevents over-excitation and quenching in sensitive phosphor regions while maintaining high conversion efficiency overall, resolving the contradiction between output and energy loss.
3Productivity
If the pump light area is increased to reduce intensity and quenching, then phosphor efficiency improves, but the geometrical efficiency of the collecting optical unit decreases
Solution Approach 1:
The patent applies local quality by optimizing the pump light area and intensity distribution for each phosphor region individually. Rather than uniformly increasing or decreasing the pump light area across all phosphors, the system tailors the illumination parameters to each phosphor's quenching characteristics. This localized optimization resolves the contradiction by maintaining high phosphor efficiency while preserving geometrical efficiency for light collection.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting pump light distribution parameters (intensity, area, spatial profile) to optimize the balance between phosphor conversion efficiency and collecting optical unit efficiency. This parameter optimization enables the system to achieve high overall efficiency without suffering from geometrical losses associated with excessive pump light area expansion.
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
This configuration enhances overall efficiency by optimizing pump light distribution across phosphors, reducing quenching and increasing conversion efficiency, particularly for phosphors that exhibit strong quenching behavior, while maintaining high pump power handling capabilities.
Implementation Method 1
a phosphor wheel for converting at least a part of the pump light into conversion light
Implementation Method 2
a pump light source, which excites the phosphor to emit light with a wavelength different to the pump light wavelength (wavelength conversion of the pump light by means of phosphor)
Data Source
AI summary
The invention provides an illumination device comprising a pump light source and a phosphor wheel. The phosphor wheel comprises at least two segmented phosphor layers. The front surfaces of the phosphor layers do not form a common plane, but instead a kind of relief in which the surfaces of the phosphor layers extend in different imaginary planes. When the phosphor wheel rotates through a beam waist of the pump. light, in this way the size of the pump light spot and therefore also the power density distribution of the pump light on the respective phosphor layer are adapted.