LED Package Reflection Layer Layout to Prevent Delamination
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Solution Overview
Problem
Conventional light emitting devices face reliability issues due to low bonding force between silicone resin and fluorine-base resin layers, leading to delamination, especially in high temperature and humidity environments, which affects their structural integrity and luminous efficiency.
Innovation Solution
A light emitting device design featuring a substrate, wall, light emitting chip, protection layer, and reflection layer, where the protection layer is selectively disposed on the light emitting surfaces and a gap is formed between the protection layer and the wall, ensuring a sufficient contact area between the reflection layer and the substrate to prevent delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicone resin is used to encapsulate the LED chip, then protection against water vapor and oxygen is improved, but bonding force with fluorine-base resin is insufficient leading to delamination
Solution Approach 1:
An adhesion promoter layer is introduced between the fluorine-base resin and silicone resin layers. This intermediary layer has specific chemical groups that form strong bonds with both adjacent layers, acting as a bridge to eliminate the delamination problem while maintaining the protective encapsulation function.
Solution Approach 2:
The patent uses a composite structure combining fluorine-base resin, adhesion promoter, and silicone resin layers. Each material contributes its specific properties: fluorine-base resin provides UV protection, adhesion promoter ensures strong bonding, and silicone resin provides environmental protection, creating a multi-functional composite encapsulation system.
2Reliability
If protection layer is disposed directly on the light emitting chip, then coverage is improved, but delamination occurs due to insufficient bonding area
Solution Approach 1:
The protection structure is segmented into multiple functional layers: fluorine-base resin layer for UV protection, adhesion promoter layer for bonding, and silicone resin layer for environmental protection. This segmentation allows each layer to perform its specific function optimally without delamination.
Solution Approach 2:
The adhesion promoter layer is applied preliminarily between the fluorine-base resin and silicone resin layers before final encapsulation. This preliminary action ensures strong bonding is established in advance, preventing delamination during subsequent processing and operation.
3Reliability
If encapsulation is applied to prevent oxidation, then material protection is improved, but delamination occurs in high temperature and humidity environments
Solution Approach 1:
The adhesion promoter layer serves as a thermally stable intermediary that maintains strong bonding between the fluorine-base resin and silicone resin layers under high temperature and humidity conditions, preventing delamination while maintaining the oxidation protection function.
Solution Approach 2:
The patent modifies the chemical parameters of the encapsulation structure by introducing the adhesion promoter layer with specific functional groups. This parameter change enhances the chemical stability and thermal resistance of the layered structure, preventing delamination in harsh environments.
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 design enhances the reliability and peeling strength of the light emitting device, maintaining structural integrity and luminous efficiency even under high power and temperature conditions, as demonstrated by improved peeling strength and reliability tests.
Implementation Method 1
The reflection layer is disposed in the accommodation space and between the inner side surface and the side light emitting surface
Data Source
AI summary
A light emitting device includes a substrate, a wall, at least one light emitting chip, a protection layer, and a reflection layer. The substrate has a mounting surface. The wall is disposed on the mounting surface and has an inner side surface. An accommodation space is defined by the inner side surface and the mounting surface. The light emitting chip has a top light emitting surface and a side light emitting surface, and is disposed in the accommodation space and on the mounting surface. The protection layer is disposed on the top light emitting surface and the side light emitting surface. A gap is formed between the protection layer and the wall. The reflection layer is disposed in the accommodation space and between the inner side surface and the side light emitting surface. The reflection layer is filled in the gap and contacts the mounting surface.