Silicone Resin Reflective Substrate for High Luminance LED Applications
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Solution Overview
Problem
Conventional reflective substrates for light emitting devices and solar cell assemblies face challenges with low reflection efficiency, heat and light resistance, yellowing, and durability issues, particularly with short wavelength light and high-intensity LED emissions, leading to decreased illumination performance and surface degradation.
Innovation Solution
A silicone resin reflective substrate with a three-dimensionally cross-linked structure containing white inorganic filler powder, such as titanium oxide, dispersed in a non-cyclic dimethylsiloxy repeating unit silicone resin, providing excellent reflectance, thermal conductivity, and chemical stability, along with a manufacturing method for forming a reflective layer by single thick coating on variously shaped support bodies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional resins (epoxy, polyamide, BT) are used for reflective substrates, then the substrate can be produced at low cost, but the viscosity is too low causing the base to be seen through the coated resin and insufficient reflection efficiency
Solution Approach 1:
The patent uses a composite material system consisting of low-viscosity resin (epoxy, polyamide, or BT resin) combined with high-refractive-index white pigment particles (titanium oxide, barium sulfate, zinc oxide, or calcium carbonate). This composite approach allows the resin to provide adequate coating coverage while the pigment particles provide the necessary light reflection, resolving the contradiction between low production cost and sufficient reflection efficiency.
2Length of stationary object
If a large amount of resin is forcibly coated to achieve desired thickness, then the coating thickness can be increased, but resin drips down and volatilization of solvent occurs causing wrinkles and unevenness in thickness
Solution Approach 1:
The patent adjusts the viscosity parameter of the resin composition by selecting appropriate resin types and ratios, and by controlling pigment loading. This optimized viscosity parameter allows the coating to maintain its shape without dripping while still achieving the desired thickness in a single coating process, eliminating wrinkles and thickness unevenness.
3Ease of manufacture
If conventional resins are used for reflective substrates, then the substrate can be produced easily at low cost, but the heat and light resistance is poor causing yellowing and degradation under high temperature and intense light
Solution Approach 1:
The patent creates a composite material system where conventional resins (epoxy, polyamide, or BT resins) are combined with specific white pigments having high refractive indices and good heat/light resistance. The resin provides ease of manufacture and coating processability, while the pigment particles provide the necessary thermal and optical stability, preventing yellowing and degradation under high temperature and intense LED light conditions.
4Temperature
If ceramics are used for reflective substrate, then the substrate has good heat resistance, but light leakage occurs and reflection efficiency is difficult to obtain
Solution Approach 1:
The patent uses a composite material system combining organic resins with high-refractive-index inorganic pigment particles. This composite approach achieves reflection efficiency comparable to or exceeding ceramic substrates through the optical properties of the pigment particles, while maintaining the heat resistance required for LED applications through the thermal stability of both the resin and pigment components.
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 silicone resin reflective substrate achieves high reflectance across a wide wavelength range, maintains white color and stability under high-intensity light and heat, and exhibits improved adhesion and durability, ensuring long-term performance and ease of production.
Implementation Method 1
a reflective layer that contains a white inorganic filler powder dispersed in a three-dimensionally cross-linked silicone resin, the white inorganic filler powder having a higher refractive index than that of the three-dimensionally cross-linked silicone resin
Implementation Method 2
the silicone resin reflective substrate exhibits superior thermal conductivity, light fastness, heat resistance
Implementation Method 3
the silicone resin reflective substrate maintains white color and stability under high-intensity light and heat, and exhibits improved adhesion and durability
Data Source
AI summary
A versatile silicone resin reflective substrate which exhibits high reflectance of high luminance light from an LED light source over a wide wavelength from short wavelengths of approximately 340-500 nm, which include wavelengths from 380-400 nm near lower limit of the visible region, to longer wavelength in the infra-red region. The silicone resin reflective substrate has a reflective layer which contains a white inorganic filler powder dispersed in a three-dimensional cross linked silicone resin, the inorganic filler powder having a high reflective index than the silicone resin. The reflective layer is formed on a support body as a film, a solid, or a sheet. The silicone resin reflective substrate can be easily formed as a wiring substrate, a packaging case or the like, and can be manufactured at low cost and a high rate of production.