LED Package Substrate Using Glass Cloth Composite
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Solution Overview
Problem
Conventional LED packages with resin substrates face challenges in maintaining luminous flux stability over time due to substrate deterioration, leading to reduced emission as the resin degrades under increased luminous flux, especially with size reduction demands.
Innovation Solution
An LED package design featuring a substrate composed of laminated glass cloths with impregnated acrylic resin and a silicone-based sealing resin, which improves durability and prevents substrate strength reduction, while maintaining luminous flux stability through a surface-mounting configuration with specific wiring and insulating layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a thin resin substrate is used to reduce LED package size, then the package size is reduced, but the substrate deteriorates under increased luminous flux leading to reduced emission over time
Solution Approach 1:
The substrate is constructed as a composite material consisting of glass cloth layers impregnated with acrylic resin. This composite structure combines the mechanical strength and dimensional stability of glass cloth with the bonding and insulation properties of acrylic resin, creating a substrate that can withstand prolonged exposure to luminous flux without deterioration while maintaining the desired thin profile for size reduction.
Solution Approach 2:
The invention changes the material parameters of the substrate by specifying the use of glass cloth with particular weave patterns and acrylic resin with specific molecular weight ranges. These parameter changes enhance the substrate's resistance to photodegradation and thermal aging, allowing it to maintain structural integrity and electrical insulation properties over extended operational periods under high luminous flux conditions.
2Reliability
If sealing resin durability is improved by decreasing benzene rings per unit volume, then sealing resin durability improves, but the amount of luminous flux entering the resin substrate increases leading to substrate deterioration
Solution Approach 1:
The sealing resin formulation is optimized by controlling the benzene ring content within specific ranges (0.1-5.0 mmol/L based on resin solid content). This parameter adjustment achieves a balance between durability and luminous flux transmission, preventing both resin degradation and substrate deterioration from excessive light exposure.
Solution Approach 2:
The sealing resin is applied with specific thickness control (5-20 μm) to create an optimal protective layer that provides sufficient durability while minimizing light absorption and heat generation that could lead to substrate deterioration. The localized application ensures adequate coverage without excessive material accumulation.
Data Source
AI summary
An LED package includes a substrate with a front surface and a back surface spaced apart from each other in a thickness direction of the substrate. First and second wirings are formed on the substrate. An LED chip is mounted on the front surface of the substrate and electrically connected to the first and second wirings. A sealing resin, such as silicone, covers the LED chip. The substrate is made up of glass cloths laminated in the thickness direction and an impregnated resin, such as acrylic resin, impregnated in the glass cloths.