Resin Composition Reflectors for LED Devices
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Solution Overview
Problem
Current resin-based reflectors for light-emitting semiconductor devices face challenges in maintaining high reflectance, durability, and resistance to yellowing, especially when exposed to short-wavelength light, leading to reduced luminance and photoreflectance.
Innovation Solution
A resin composition incorporating an oxide of a rare earth element as an inorganic filler, combined with organic resins like polyphthalamide or silicone, which provides enhanced heat resistance, moisture resistance, and light resistance, maintaining high reflectance and luminance even under intense short-wavelength light exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional pigments (alumina, magnesium oxide, antimony oxide, aluminum hydroxide, barium sulfate, magnesium carbonate, barium carbonate) are used to maintain reflectance of 80% or higher in the wavelength range of 350 to 800 nm, then the reflectance requirement is met, but the pigment must be added in large amounts and non-alumina pigments have high moisture absorbance and water solubility leading to reliability problems
Solution Approach 1:
The patent changes the chemical composition parameter by replacing conventional pigments with rare earth element oxides (Yttrium oxide, Lanthanum oxide, Cerium oxide, Gadolinium oxide) that have superior optical and chemical stability. This parameter change enables achieving 80% or higher reflectance in the 350-800 nm range while simultaneously improving moisture resistance and eliminating the reliability issues associated with high moisture absorbance and water solubility of conventional pigments
Solution Approach 2:
The patent creates a composite material system combining epoxy resin with specific ratios of rare earth element oxides (10-100% of total inorganic filler) and other inorganic fillers (alumina, silica, titanium oxide). This composite approach optimizes both optical performance (reflectance) and chemical stability (moisture resistance) by leveraging the complementary properties of different materials in controlled proportions
2Ease of manufacture
If PPA resin or epoxy resin is used in reflectors for light-emitting diodes that emit intense short-wavelength light, then the reflector can be molded with good processability, but the resin is degraded and discolored by the light and the reflectance is lowered
Solution Approach 1:
The patent changes the chemical composition parameters of the resin system by using epoxy resin with specific molecular structure and crosslinking characteristics, combined with rare earth element oxides. This parameter change provides superior resistance to short-wavelength light degradation while maintaining good moldability, preventing the resin from being degraded and discolored by intense short-wavelength light from LEDs
Solution Approach 2:
The patent replaces PPA resin which has limited light resistance with epoxy resin systems that provide long-term stability. The epoxy-based reflector materials offer durable performance under intense short-wavelength light exposure, eliminating the need for frequent replacement due to degradation and discoloration
3Illumination intensity
If a white pigment is added in large amounts to maintain reflectance of 80% or higher in the wavelength range of 350 to 800 nm, then the reflectance requirement is met, but the cost and material usage increase
Solution Approach 1:
The patent changes the optical parameters by using rare earth element oxides which have superior light scattering and reflection properties compared to conventional white pigments. This parameter change enables achieving 80% or higher reflectance in the 350-800 nm range with reduced pigment loading, lowering both material cost and the quantity of substance required
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 resin composition achieves high photoreflectance and luminance stability, with the rare earth oxide filler ensuring effective light reflection and durability, making it suitable for light-emitting semiconductor devices emitting wavelengths up to 500 nm.
Implementation Method 1
a reflector having an optimal reflectance as a reflector for a light-emitting semiconductor device, which in particular has wavelengths of up to 500 nm
Data Source
Figure 1A~2
Figure 3A~4
Figure 5A~5B
AI summary
Disclosed herein is a resin composition including 100 parts by weight of an organic resin and 50 to 1,000 parts by weight of an inorganic filler, wherein 10 to 100% of the inorganic filler is composed of an oxide of a rare earth element.