LED Package Resin Encapsulant Micro Rough Pattern
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Solution Overview
Problem
Conventional light emitting diode packages experience low light extraction efficiency due to the refractive index mismatch between the resin encapsulant and the external atmosphere, as well as the formation of a curved surface by the resin, which limits the extraction of light emitted from the diode chip.
Innovation Solution
A method involving a micro rough pattern is applied to the surface of the resin encapsulant using a stamp with engraved micro features, which is applied after partially curing the resin to ensure pattern integrity, thereby enhancing light extraction efficiency by flattening the resin surface and increasing the number of inclined surfaces for light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a liquid transparent resin is injected to form the resin encapsulant, then the encapsulant is formed in the recess, but the resin forms a curved surface due to wettability which results in low light extraction efficiency
Solution Approach 1:
A stamp with a micro rough pattern is applied to the liquid-state transparent resin before complete curing, preliminarily forming the desired surface structure. This preliminary action prevents the curved surface formation that would otherwise occur due to resin wettability, ensuring the surface is ready for optimal light extraction before the resin sets.
Solution Approach 2:
The stamp introduces local micro rough patterns (convex and concave portions) to specific regions of the resin encapsulant surface. These localized structural variations create multiple light extraction paths and angles, improving light extraction efficiency in those specific areas without affecting the overall encapsulant structure.
2Ease of manufacture
If a smooth surface resin encapsulant is formed, then the manufacturing process is simple, but light extraction efficiency is limited by the refractive index mismatch between the resin and external atmosphere
Solution Approach 1:
The surface parameters of the resin encapsulant are changed by introducing micro rough patterns through stamping. This modifies the surface topology from smooth to textured, creating convex and concave portions that alter light propagation paths and improve extraction efficiency while maintaining compatibility with the existing manufacturing process.
Solution Approach 2:
The micro rough pattern is preliminarily formed on the resin surface during the encapsulant formation process itself, before final curing. This integrates the surface structure modification into the manufacturing flow without requiring separate complex processing steps, maintaining ease of manufacture while improving optical performance.
3Stability of the object's composition
If the stamp is applied after the resin is completely cured, then the resin structure is stable, but the micro rough pattern cannot be formed on the resin surface
Solution Approach 1:
The stamp is applied at the optimal moment when the resin is partially cured but still sufficiently pliable to accept the micro rough pattern. This preliminary timing ensures the resin has enough stability to hold the pattern without deforming, while remaining soft enough to allow complete replication of the stamp's micro features.
Solution Approach 2:
The manufacturing process utilizes the dynamic state of the resin during curing transition. By applying the stamp during this transitional phase when the resin's physical properties are changing from liquid to solid, the process captures the optimal window where the resin is neither too fluid nor too rigid, enabling successful pattern transfer.
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 method significantly improves light extraction efficiency by 8 to 43% compared to conventional packages, effectively addressing the limitations of refractive index mismatch and curved surface issues, resulting in enhanced light emission.
Implementation Method 1
curing the liquid-state transparent resin with the stamp applied thereon to form a resin encapsulant
Data Source
AI summary
A method of manufacturing a light emitting diode package. A cup-shaped package structure with a recess formed therein and an electrode structure formed on a bottom of the recess is prepared. A light emitting diode chip is mounted on a bottom of the recess with a terminal of the chip electrically connected to the electrode structure. A liquid-state transparent resin is injected in the recess and before the liquid-state transparent resin is completely cured, a stamp with a micro rough pattern engraved thereon is applied on an upper surface of the resin. The liquid-state transparent resin is cured with the stamp applied thereon to form a resin encapsulant and the stamp is removed from the resin encapsulant.