LED Package Stress Release Grooves for Thermal Expansion
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Solution Overview
Problem
Light-emitting device packages face reliability and durability issues due to thermal stress caused by differences in thermal expansion coefficients between conductive regions and the electrode separator, leading to potential cracks and reduced product lifespan.
Innovation Solution
A light-emitting device package design featuring a package substrate with first and second conductive regions separated by an electrode separator and surrounded by a stress release portion with varying widths, which alleviates thermal stress and evenly distributes heat, preventing crack formation and extending product life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive regions and electrode separator are directly connected without stress release structure, then electrical connection is achieved, but thermal stress causes cracks and reduces reliability
Solution Approach 1:
The patent introduces a stress release portion with a groove structure before thermal stress can cause damage. This groove structure acts as a cushioning element that absorbs and distributes thermal stress, preventing crack formation at the interface between conductive regions and electrode separator, thereby maintaining product reliability under thermal expansion conditions.
Solution Approach 2:
The stress release portion is localized at specific critical areas where thermal stress concentrates, rather than modifying the entire structure. The groove is positioned strategically at the interface between conductive regions and electrode separator, providing targeted stress relief where it is most needed while maintaining overall structural integrity.
2Ease of manufacture
If uniform stress release structure is used, then manufacturing is simplified, but thermal stress distribution remains uneven
Solution Approach 1:
The stress release portion employs an asymmetric groove structure with varying widths - a wider first groove and a narrower second groove. This asymmetric design creates different stress relief capacities at different locations, enabling more uniform thermal stress distribution across the structure while remaining manufacturable through standard patterning processes.
Solution Approach 2:
Different sections of the stress release portion have different groove widths tailored to local stress requirements. The wider first groove addresses areas with higher stress concentration, while the narrower second groove provides appropriate relief in lower-stress regions, optimizing overall stress distribution.
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 effectively reduces thermal stress on the light-emitting device, preventing cracks and extending its lifespan by evenly distributing heat and alleviating thermal expansion coefficient differences.
Implementation Method 1
thermal stress caused by differences in thermal expansion coefficients between conductive regions and the electrode separator
Implementation Method 2
An electrode separator extends across the package substrate while penetrating the package substrate between the first and second conductive regions to electrically separate the first and second conductive regions from each other
Data Source
AI summary
A light-emitting device package is provided including: a package substrate and a light-emitting device mounted on the package substrate. The package substrate includes first and second conductive regions each having a portion overlapping the light-emitting device. An electrode separator extends across the package substrate while penetrating the package substrate between the first and second conductive regions to electrically separate the first and second conductive regions from each other. A stress release portion surrounds at least a portion of each of the first and second conductive regions at an edge part of the package substrate. The stress release portion has different widths on both sides of the electrode separator interposed therebetween.