Phosphor Element with Low Refractive Index Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing phosphor elements that use reflection to convert excitation light into fluorescence suffer from reduced fluorescence intensity due to high photon absorption and scattering, leading to temperature increases and color unevenness in the emitted white light, limiting their effectiveness in maintaining intensity over time.
Innovation Solution
A phosphor element with an integral low refractive index layer on its side and opposing faces, covered by an integral reflection film, where the incident face area is larger than the opposing face area, reduces the number of reflections and facilitates heat dissipation, enhancing fluorescence intensity and preventing color unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the intensity of the excitation light is raised to improve fluorescence intensity in reflection type phosphor elements, then the fluorescence intensity increases, but the temperature of the phosphor is raised due to high photon absorption and scattering from multiple reflections
Solution Approach 1:
The patent inverts the conventional transmission-type phosphor element design by creating a reflection-type element where the incident face and emitting face are on the same side. This inversion allows excitation light to enter through the incident face, reflect off the opposing face with reflective coating, and return through the incident face as fluorescence, reducing the number of reflections compared to conventional designs and thereby reducing heat generation while maintaining fluorescence intensity
Solution Approach 2:
The patent changes the optical path parameters by designing a specific geometric configuration where the incident face area is larger than the opposing face area, and the side faces are inclined at specific angles. This parameter optimization reduces the number of reflections needed for light to exit the phosphor element, thereby reducing photon absorption and scattering losses that generate heat, while maintaining high fluorescence intensity
2Productivity
If the number of reflections is increased to improve light extraction in reflection type phosphor elements, then more light can be emitted, but photon absorption and scattering increase leading to color unevenness in the emitted white light
Solution Approach 1:
The patent employs asymmetric geometry where the incident face area is deliberately made larger than the opposing face area, and side faces are inclined at specific asymmetric angles. This asymmetric design optimizes the optical path to minimize the number of reflections required for light extraction, thereby reducing photon absorption and scattering that cause color unevenness, while maintaining high light extraction efficiency
Solution Approach 2:
By inverting the conventional design to place both incident and emitting faces on the same side with reflective coating on the opposing face, the patent creates an optimized reflection path that reduces the number of internal reflections compared to conventional transmission-type designs, thereby maintaining color uniformity while improving light extraction
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 maintains high fluorescence intensity and prevents color unevenness in the emitted white light, while also improving heat dissipation from the phosphor element, ensuring consistent performance over time.
Implementation Method 1
the phosphor part converting at least a part of the excitation light incident onto the incident face into a fluorescence and emitting the fluorescence from the incident face
Implementation Method 2
an integral low refractive index layer on side faces and the opposing face of the phosphor part... the number of reflections is high, resulting in the disappearance of photons due to absorption and scattering by the reflection
Implementation Method 3
an integral reflection film covering a surface of the low refractive index layer
Data Source
AI summary
A phosphor element includes: a phosphor part having an incident face for excitation light, an opposing face opposing the incident face, and a side face, the phosphor part converting at least a part of the excitation light incident onto the incident face into a fluorescence and emitting the fluorescence from the incident face; an integral low refractive index layer on the side face and opposing face of the phosphor part and having a refractive index lower than that of the phosphor part; and an integral reflection film covering a surface of the low refractive index layer. The area of the incident face of the phosphor part is larger than the area of the opposing face.