Composite Oxide Particle Reflector for LED Light Management
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Solution Overview
Problem
Conventional reflectors for light-emitting semiconductor devices face issues such as degradation and yellowing due to temperature and light exposure, poor flowability of resin compositions with high-brightness LEDs, and light loss due to similar refractive indices of filler materials like silica and silicone resins.
Innovation Solution
A composite particle is created by sintering a mixture of finely powdered silica with a high BET specific surface area and liquid metal alkoxides or nano-order metal oxides, which is then incorporated into a thermosetting resin composition to form a reflector that maintains high light reflectance and minimizes light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a large amount of fine powder of titanium oxide or the like is used to ensure a white color, then the light reflectance is improved, but the flowability of the resin deteriorates and molding defects occur more frequently
Solution Approach 1:
The invention changes the particle size parameter of the filler material from fine powder (conventional) to coarse particles (invention: 10-200 μm average diameter). This parameter change resolves the contradiction by maintaining light reflectance through proper particle size selection while eliminating the flowability problems associated with fine powders during molding processes.
Solution Approach 2:
The invention uses composite filler materials consisting of coarse particles of silica, aluminum oxide, and zinc oxide in specific combinations. This composite approach maintains the white color and light reflectance properties while improving resin flowability and reducing molding defects compared to using fine titanium oxide powder alone.
2Illumination intensity
If silica is used as a filler material, then the white color is maintained, but some of the emitted light escapes due to similar refractive index of silica to that of the silicone resin
Solution Approach 1:
The invention applies local quality by using multiple types of filler particles with different refractive indices (silica, aluminum oxide, zinc oxide) rather than a single uniform material. This creates local variations in refractive index throughout the resin matrix, reducing light escape while maintaining the overall white color appearance.
Solution Approach 2:
The invention employs composite filler materials combining silica, aluminum oxide, and zinc oxide in specific ratios. This composite structure addresses the refractive index matching problem by introducing materials with different optical properties, thereby reducing light transmission losses while preserving the white color effect.
3Ease of manufacture
If thermoplastic resin or epoxy resin is used for the reflector, then the manufacturing process is simplified, but the resin degrades and yellows due to the effects of temperature and light
Solution Approach 1:
The invention changes the chemical composition parameter of the resin from conventional thermoplastic or epoxy resins to a specific silicone resin formulation. This parameter change maintains ease of manufacturing while dramatically improving resistance to thermal and light-induced degradation and yellowing.
Solution Approach 2:
The invention uses composite resin formulations combining silicone resin with specific filler materials (coarse silica, aluminum oxide, zinc oxide particles). This composite structure provides both the manufacturing advantages of conventional resins and the superior thermal and light stability of silicone-based materials.
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 provides a reflector material with improved light reflectance and reduced light transmission, allowing for effective encapsulation of light-emitting semiconductor devices without degradation, while maintaining mechanical strength and optical properties.
Implementation Method 1
the composite particle is prepared by mixing or kneading the raw materials to obtain a sol or gel-like substance, subsequently sintering the sol or gel-like substance at a temperature of 300° C. or higher to form a glass-like substance
Data Source
AI summary
A composite oxide particle prepared from raw materials comprising: (1) a finely powdered silica having a BET specific surface area of 50 m2/g or greater or an alkoxysilane, and (2) a liquid metal alkoxide other than an alkoxysilane or a nano order metal oxide powder other than finely powdered silica, one of components (1) and (2) being a solid oxide and the other being a liquid alkoxide, wherein the composite oxide particle is prepared by mixing or kneading the raw materials to obtain a sol or gel-like substance, sintering the sol or gel-like substance at a temperature of 300° C. or higher to form a glass-like substance, and then crushing the glass-like substance is provided. Also, a resin composition containing the composite oxide particle, and a reflector for a light-emitting semiconductor device formed using the resin composition are provided. The invention is able to provide a resin composition which is ideal as a reflector material for a light-emitting semiconductor device that exhibits high light reflectance and minimal light transmission, and a composite oxide particle that is added to the resin composition.