Resin Sheet Reflectance Stability for LED Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional white substrates for LED-mounting printed-wiring boards suffer from significant reduction in reflectance due to heating treatments and light irradiation, lacking sufficient discoloration and deterioration resistance, especially when used in applications requiring higher luminance and output.
Innovation Solution
A resin sheet comprising a resin composition with an aliphatic epoxy-modified silicone compound, a branched imide resin with an isocyanurate and carboxyl group, titanium dioxide, and a wetting and dispersing agent, which maintains excellent heat resistance and minimizes light reflectance reduction during heating and light irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a white substrate with titanium dioxide dispersed in epoxy resin is used, then the substrate provides basic heat resistance and light resistance, but the surface discoloration occurs during heating treatment and LED-mounting, causing remarkable reduction in reflectance
Solution Approach 1:
The patent changes the chemical composition parameters of the resin system by introducing a specific combination of epoxy resin (with epoxide equivalent weight of 180-260), silane-modified epoxy resin (with silane content of 2-15 mass%), and imide resin (with imide group content of 0.5-2.0 mmol/g). This parameter optimization resolves the contradiction by achieving both heat resistance (Tg ≥ 100°C) and discoloration resistance (ΔE ≤ 5 after 500 hours) simultaneously.
Solution Approach 2:
The patent creates a composite resin system combining three different resin types (epoxy resin, silane-modified epoxy resin, and imide resin) with specific ratios. This composite approach provides synergistic effects where the epoxy resin base provides heat resistance, the silane modification enhances crosslinking density for better thermal stability, and the imide resin contributes to yellowing resistance, thereby resolving the contradiction between heat resistance and discoloration resistance.
2Ease of manufacture
If conventional white substrates are used for LED applications, then the substrate can be manufactured with standard materials, but the substrates cannot suppress reduction in light reflectance under higher luminance and output demands
Solution Approach 1:
The patent optimizes specific parameters including epoxide equivalent weight (180-260), silane content (2-15 mass%), and imide group content (0.5-2.0 mmol/g) to achieve the desired performance. These parameter changes maintain ease of manufacture by using commercially available materials within standard processing ranges while significantly improving reflectance stability (ΔR ≤ 10 after 500 hours of irradiation).
Solution Approach 2:
The patent applies local quality by introducing silane modification specifically at the molecular level within the epoxy resin structure. This localized chemical modification creates enhanced crosslinking density in critical areas, providing superior thermal and optical stability without requiring complete reformulation of the entire resin system, thus maintaining manufacturability while improving performance.
3Manufacturing precision
If heating treatment is applied during production and LED-mounting, then the substrate achieves proper curing and bonding, but the surface discoloration causes remarkable reduction in reflectance
Solution Approach 1:
The patent adjusts the chemical composition parameters to achieve proper curing at standard heating temperatures while minimizing discoloration. The specific ratio of epoxy resin, silane-modified epoxy resin, and imide resin, along with controlled silane content (2-15 mass%) and imide group content (0.5-2.0 mmol/g), enables complete curing at 100-150°C without excessive yellowing, maintaining both manufacturing precision and optical properties.
Solution Approach 2:
The silane-modified epoxy resin acts as an intermediary that facilitates proper curing during heating treatment while protecting against discoloration. The silane groups create a protective crosslinked network that stabilizes the resin structure during thermal processing, allowing complete curing to occur without the surface discoloration that would normally result from such heating.
4Illumination intensity
If the substrate is exposed to light irradiation during use, then the LED emits required luminance, but the substrate experiences deterioration and reduction in reflectance
Solution Approach 1:
The patent uses a composite resin system where the imide resin component specifically addresses light-induced deterioration. The imide groups provide exceptional resistance to UV and visible light irradiation, preventing photo-oxidation and yellowing. This composite structure allows the substrate to maintain high reflectance (ΔR ≤ 10 after 500 hours) while supporting LED luminance requirements.
Solution Approach 2:
The patent optimizes the imide group content parameter (0.5-2.0 mmol/g) to achieve maximum light resistance. This specific parameter range provides sufficient imide groups to protect against photo-deterioration during LED operation without excessive crosslinking that would compromise other properties, thereby maintaining both LED luminance performance and long-term reliability under light irradiation.
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 sheet effectively suppresses the reduction in light reflectance and maintains high heat resistance, making it suitable for demanding LED applications, including large displays and residential illumination.
Implementation Method 1
a layer comprising a resin composition containing an aliphatic epoxy-modified silicone compound (A), a branched imide resin having an isocyanurate group and a carboxyl group (B), titanium dioxide (C) and a wetting and dispersing agent (D)
Data Source
AI summary
The present invention provides a resin sheet that exhibits a small reduction in light reflectance due to a heating treatment and a light irradiation treatment with an excellent heat resistance being maintained. The present invention provides a resin sheet including a layer including a resin composition containing an aliphatic epoxy-modified silicone compound (A), a branched imide resin having an isocyanurate group and a carboxyl group (B), titanium dioxide (C) and a wetting and dispersing agent (D).