External Electrode Resin Structure for Crack-Resistant Components
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Solution Overview
Problem
Existing electronic components are prone to cracking due to stress concentration at the end edges of external electrodes when solder-mounted on electronic devices.
Innovation Solution
The electronic component design includes an element body with a sintered metal layer, a conductive resin layer, and a plating layer, where the conductive resin layer covers the end edges of the sintered metal layer and the external electrodes, reducing stress concentration and preventing crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external electrodes are disposed on the element body for electrical connection, then electrical functionality is achieved, but stress concentration occurs at the end edges of the external electrodes causing cracks in the element body
Solution Approach 1:
The patent applies local quality by forming a conductive resin layer specifically at the end edges of the external electrodes where stress concentration occurs. This localized modification provides stress distribution functionality only where needed, without changing the structure of the entire electrode system. The conductive resin layer has different mechanical properties compared to the sintered metal layer, creating a gradient structure that mitigates stress concentration at the critical end edge regions.
2Reliability
If the end edge of the external electrode serves as stress concentration point, then electrical connection is established, but the end edge becomes an origination for crack formation
Solution Approach 1:
The conductive resin layer acts as an intermediary between the sintered metal layer and the solder fillet. This intermediate layer has intermediate mechanical properties that bridge the stiff sintered metal and the compliant solder, distributing stresses more evenly. The conductive resin layer absorbs and redistributes the concentrated stresses that would otherwise be transmitted directly to the element body at the end edges, preventing crack initiation.
3Strength
If solder fillet is formed for mounting the electronic component, then mechanical bonding is achieved, but external force is applied onto the element body through the external electrode causing stress concentration
Solution Approach 1:
The conductive resin layer is formed beforehand at the end edges of the external electrodes as a protective cushioning layer. This layer is designed to absorb and distribute the external forces that will be applied during soldering and subsequent operation. By having this stress-distributing layer in place before mounting, the element body is protected from direct stress concentration that would occur without it.
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
This design effectively suppresses the occurrence of cracks in the element body by distributing stress evenly and preventing concentration at the end edges of the external electrodes, thereby enhancing the reliability and durability of the electronic component.
Implementation Method 1
The conductive resin layer covers the end edges of the sintered metal layer and the external electrodes, reducing stress concentration and preventing crack formation
Data Source
AI summary
An element body includes a principal surface arranged to constitute a mounting surface, an end surface, and a side surface coupling the principal surface and the end surface. An external electrode is disposed on the element body and includes a conductive resin layer. An internal conductor is disposed in the element body and is exposed to the end surface. The element body includes a ridge portion between the end surface and the side surface, the ridge portion including a first region exposed from the conductive resin layer and a second region positioned closer to the principal surface than the first region and covered with the conductive resin layer.