Segmented Ceramic Phosphor Array for Thermal Stress Relief
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Solution Overview
Problem
High-power density in light sources using ceramic phosphors leads to heat management issues, resulting in potential failures such as crack formation and delamination due to non-uniform optical load.
Innovation Solution
A luminescent element comprising a plurality of element bodies with a luminescent material and light transmissive bodies, arranged in a 2D configuration and in thermal contact with a thermally conductive support, to enhance heat dissipation and prevent localized stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a ceramic phosphor is used in high-power density light sources, then brightness and light intensity are improved, but heat management issues arise leading to crack formation and delamination
Solution Approach 1:
The ceramic phosphor is divided into multiple small individual ceramic phosphors rather than using a single large phosphor. This segmentation allows each small phosphor to be independently mounted on the heat sink with its own thermal contact, distributing the thermal load and preventing localized stress concentration that causes cracking and delamination in high-power applications.
2Illumination intensity
If a reflective layer is coated on the phosphor to improve reflectivity, then light reflection efficiency is improved, but adhesion failures occur under high optical load
Solution Approach 1:
By segmenting the phosphor into multiple small individual ceramic phosphors, the reflective layer on each small phosphor experiences reduced stress from optical loading. This prevents delamination and adhesion failures that occur when a single large phosphor with reflective coating is subjected to high optical power density.
3Illumination intensity
If multiple luminescent materials are used to achieve full color gamut, then color rendering is improved, but thermal management complexity increases
Solution Approach 1:
Different luminescent materials are applied to different individual ceramic phosphors rather than combining multiple materials in a single phosphor. This segmentation allows each phosphor to be optimized for specific wavelength conversion while maintaining uniform thermal contact with the heat sink, simplifying thermal management compared to multi-material single-phosphor approaches.
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 proposed solution effectively manages thermal loads, reducing the risk of delamination and crack formation, while improving thermal dissipation pathways and light distribution, leading to higher brightness and stability in high-power light sources.
Implementation Method 1
the luminescent material is configured to convert at least part of first radiation, selected from one or more of UV radiation and visible radiation, into luminescent material light
Implementation Method 2
the plurality of element bodies are configured in thermal contact with the thermally conductive support
Data Source
AI summary
The invention provides a light generating device (1000) comprising a light source (10) and a luminescent element (20), wherein:—the light source (10) is configured to generate the first radiation (11); wherein the light source (10) comprises a laser light source;—the luminescent element (20) comprises (i) a plurality of element bodies (200) and (ii) a thermally conductive support (400); wherein the plurality of element bodies (200) comprises a plurality of first bodies (210) and a plurality of second bodies (220);—the plurality of first bodies (210) comprise a luminescent material (50), wherein the luminescent material (50) is configured to convert at least part of first radiation (11), selected from one or more of UV radiation and visible radiation, into luminescent material light (51); wherein the first bodies have a first thermal conductivity K1; wherein the first bodies (210) are configured in a light receiving relationship with the light source (10);—the plurality of second bodies (220), different from the first bodies (210) are light transmissive for one or more wavelengths of the first radiation (11) and the luminescent material light (51); wherein the second bodies (220) have a second thermal conductivity K2, wherein K2≥0.2*K1;—the plurality of first bodies (210) and the plurality of second bodies (220) are configured in a 2D arrangement (205), wherein for a plurality of second bodies (220) applies that they are configured adjacent to different first bodies (210); and—the plurality of first bodies (210) and second bodies (220) are configured in thermal contact with the thermally conductive support (400).