Ceramic Protection Layer for Light Converting Device
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Solution Overview
Problem
High-intensity blue laser light and heat generated by light conversion in phosphor-based light sources lead to reliability issues and inefficient heat dissipation, particularly in high-luminance applications.
Innovation Solution
A light converting device with a ceramic protection layer is introduced, which is mechanically and thermally coupled to a substrate functioning as a heatsink, featuring a reflective structure with a ceramic protection layer that inhibits mechanical damage and chemical reactions, scatters light, and maintains high reflectivity, while being thin enough to avoid optical and thermal performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a reflective structure is used to reflect laser light and converted light, then optical efficiency is improved, but the reflective structure is susceptible to mechanical damage and chemical reactions (corrosion)
Solution Approach 1:
A translucent ceramic protection layer is introduced as an intermediary between the reflective structure and the light converter. This protection layer shields the reflective metal surface from mechanical damage and chemical corrosion while allowing laser light and converted light to pass through, thus maintaining high optical efficiency without compromising the reliability of the reflective structure
Solution Approach 2:
The device employs a composite structure combining a metal reflective surface with a translucent ceramic protection layer. The ceramic material provides mechanical strength and chemical resistance, while its translucency preserves optical performance, creating a composite system that simultaneously addresses both reliability and optical efficiency requirements
2Reliability
If a protection layer is added to protect the reflective structure, then reliability is improved, but the layer may absorb light and reduce optical efficiency
Solution Approach 1:
The ceramic protection layer is specifically selected and engineered with controlled optical parameters including transmittance greater than 80%, refractive index between 1.5 and 2.5, and thickness between 1 μm and 100 μm. These parameter optimizations ensure the protection layer provides adequate mechanical and chemical protection while minimizing light absorption and maintaining high optical efficiency
3Reliability
If the ceramic protection layer is made thicker to improve protection, then mechanical and chemical resistance is improved, but light scattering increases and optical performance degrades
Solution Approach 1:
The thickness of the ceramic protection layer is precisely controlled within the range of 1 μm to 100 μm. This optimized thickness provides sufficient mechanical strength and chemical resistance while minimizing light scattering effects, thereby balancing protection requirements with optical performance without excessive light loss
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 the reliability and optical efficiency of the light converting device by preventing mechanical damage and chemical reactions, ensuring efficient heat dissipation and maintaining high reflectivity, thus addressing the reliability and heat dissipation challenges in high-luminance light sources.
Implementation Method 1
The ceramic protection layer may be arranged to scatter the laser light and converted light. The ceramic protection layer may, for example, comprise scattering structures (e.g. particles or pores) with a size between 10 nm and 10 μm
Implementation Method 2
The reflective structure comprises at least one reflective metal surface arranged to reflect laser light and converted light. The reflectivity of the reflective structure is preferably more than 90%, more preferably more than 95% and most preferably more than 98%
Implementation Method 3
The substrate is arranged to dissipate heat, thus functions as a heatsink
Data Source
AI summary
A light converting device, comprising:a substrate functioning as a heatsink,a light converter adapted to convert laser light to converted light, wherein a peak emission wavelength of the converted light is in a longer wavelength range than a laser peak emission wavelength of the laser light, the light converter comprises a light entrance surface, a bonding surface opposite to the light entrance surface and at least one side surface, the bonding surface is mechanically and thermally coupled to the substrate,a reflective structure attached to or part of the substrate, wherein the reflective structure comprises at least one reflective metal surface arranged on the side of the substrate facing the light converter to reflect laser light and converted light, anda translucent ceramic protection layer, arranged between the reflective structure and the light converter, and having a thickness of less than 50 μm.