Ceramic Phosphor Light Source with Substrate Distance Optimization
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Solution Overview
Problem
Existing light source apparatuses using phosphors suffer from decreased excitation light utilization efficiency due to stray light reflections at the phosphor-substrate interface, leading to inefficient fluorescence emission.
Innovation Solution
A light source apparatus with a transmissive ceramic phosphor supported by a non-light-transmissive substrate, where the distance from the excitation light irradiated region to the substrate is 0.34 mm or greater, preventing direct excitation light absorption and enhancing fluorescence extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the phosphor is provided on a transparent substrate with excitation light passing through the substrate, then the phosphor can be supported structurally, but part of the excitation light is reflected off the interface between the phosphor and substrate to form stray light, resulting in decreased excitation light utilization efficiency
Solution Approach 1:
A light-transmitting resin layer is introduced as an intermediary between the transparent substrate and the phosphor layer. This resin layer has a refractive index that is optimized to reduce reflection at the interface, thereby minimizing stray light formation while maintaining structural support. The resin acts as a mediator that improves optical coupling between the substrate and phosphor, resolving the contradiction between structural integrity and light utilization efficiency.
2Loss of energy
If the distance from the irradiated region to the substrate is increased to 0.34 mm or greater, then excitation light utilization efficiency is improved, but the overall device structure becomes more complex
Solution Approach 1:
The invention optimizes the distance parameter between the irradiated region of the phosphor and the substrate to be 0.34 mm or greater. This specific parameter change ensures that excitation light that has passed through the phosphor does not reflect off the substrate interface and return to the phosphor, thereby improving excitation light utilization efficiency. The parameter optimization balances structural simplicity with performance improvement.
3Illumination intensity
If a transmissive phosphor unit is used to allow excitation light to pass through, then fluorescence emission can be achieved, but stray light is generated at the phosphor-substrate interface leading to decreased efficiency
Solution Approach 1:
The light-transmitting resin layer serves as an intermediary that improves the optical interface between the transparent substrate and phosphor. By optimizing the refractive index matching, the resin reduces reflection losses and minimizes stray light generation, thereby maintaining high fluorescence emission efficiency while improving excitation light utilization.
Solution Approach 2:
The invention optimizes the distance parameter to 0.34 mm or greater between the irradiated region and substrate, which prevents reflected excitation light from re-entering the phosphor. This parameter change ensures that fluorescence emission is maintained while excitation light utilization efficiency is improved by preventing energy loss through reflection.
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 improves excitation light utilization and fluorescence emission efficiency, achieving a desired white balance with a BY ratio between 30% and 50%, while allowing for easier manufacturing and heat dissipation, and enabling the generation of high-quality images in projectors.
Implementation Method 1
a ceramic phosphor having a first surface and a second surface, converts in terms of wavelength part of the excitation light outputted from the excitation light source and incident on the first surface to fluorescence, and emits the fluorescence from the second surface
Data Source
AI summary
A light source apparatus according to an aspect of the present disclosure includes an excitation light source that outputs excitation light, a ceramic phosphor that has a first surface and a second surface, converts in terms of wavelength part of the excitation light outputted from the excitation light source and incident via the first surface to generate fluorescence, and causes the fluorescence to exit via the second surface, and a substrate that supports the first surface of the ceramic phosphor. The excitation light outputted from the excitation light source is incident on an exposed portion of the first surface of the ceramic phosphor that is the portion exposed via the substrate. The distance in the exposed portion from an irradiated region irradiated with the excitation light to the substrate is 0.34 mm or greater.