Multilayer Ceramic Capacitor Moisture Resistance
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Solution Overview
Problem
Multilayer ceramic capacitors with wraparound external electrodes face challenges in maintaining moisture resistance due to clearances between the electrodes and dielectric layers, which can lead to reduced strength and increased vulnerability to water ingress.
Innovation Solution
The capacitors incorporate supplementary dielectric layers covering the spaces between the wraparound parts of the external electrodes, with surface conductor films that fill in these clearances, ensuring continuous coverage and enhanced moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the height of the capacitor body is reduced to achieve smaller size, then the size is improved, but the strength of the capacitor body drops
Solution Approach 1:
The patent introduces wraparound parts that extend from the end surfaces along the length direction onto the height-direction faces of the capacitor body. This dimensional extension provides additional structural support on the height-direction faces without increasing the overall height of the capacitor body, thus improving strength while maintaining compact size.
2Strength
If dielectric layers are used to cover the spaces between wraparound parts to maintain strength, then the strength is improved, but clearances may open due to dimensional tolerances which reduces moisture resistance
Solution Approach 1:
The patent introduces conductor films as intermediary elements that extend from the end surfaces along the length direction onto the height-direction faces, making contact with the wraparound parts. These conductor films serve as mediators that bridge the gap between wraparound parts, providing both structural support and continuous coverage that prevents water ingress, thus simultaneously improving strength and moisture resistance.
Solution Approach 2:
The patent merges the structural support function and the moisture protection function into a single integrated structure. The conductor films are positioned to make contact with the wraparound parts, creating a continuous barrier that simultaneously reinforces the capacitor body structure and prevents water ingress through clearances, eliminating the need for separate dielectric layers.
3Ease of manufacture
If clearances exist between wraparound parts and dielectric layers due to dimensional tolerances, then manufacturing is simplified, but water can enter easily which reduces moisture resistance
Solution Approach 1:
The conductor films act as intermediary elements that extend onto the height-direction faces and make contact with the wraparound parts. This intermediary structure maintains manufacturing simplicity by allowing clearances to exist while still providing continuous coverage through the conductor films, preventing water ingress without requiring tight tolerances between wraparound parts and dielectric layers.
Data Source
AI summary
In an embodiment, a multilayer ceramic capacitor 10 has supplementary dielectric layers 11d covering the spaces between two first base conductor films 11c on both height-direction faces of a capacitive element 11', respectively, in such a way that clearances CL are left between the first base conductor films 11c and the supplementary dielectric layers 11d in the length direction. External electrodes 12, 13 each have a second base conductor film 12a, 13a and a surface conductor film 12b, 13b, and the wraparound locations 12b1, 13b1 of each surface conductor film 12b, 13b have insertion parts 12b2, 13b2 that fill in the clearances CL. The multilayer ceramic capacitor can mitigate deterioration in moisture resistance.