Multilayer Ceramic Capacitor Structure for Crack Containment
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Solution Overview
Problem
Conventional multilayer ceramic capacitors suffer from cracks forming at pores, which can propagate to internal electrode layers, leading to insulation degradation and dielectric breakdown.
Innovation Solution
The multilayer ceramic capacitor design incorporates dielectric layers with unevenly distributed pores, having different pore area occupancy percentages, to preferentially form cracks at interfaces between layers, preventing them from reaching internal electrode layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pores are present in dielectric layers, then manufacturing is easier and cost is reduced, but cracks form from pores and propagate to internal electrode layers causing insulation degradation
Solution Approach 1:
The patent applies local quality by creating dielectric layers with non-uniform pore distribution. Specifically, the intermediate dielectric layer has a different average pore area occupancy percentage compared to the first and second dielectric layers. This local variation in pore density creates a barrier that prevents cracks from propagating uniformly through all layers, thereby maintaining insulation reliability while preserving manufacturing ease.
2Manufacturing precision
If pores are uniformly distributed in dielectric layers, then manufacturing precision is improved, but cracks propagate through pores to reach internal electrode layers
Solution Approach 1:
The patent applies asymmetry by intentionally creating asymmetric pore distribution across different dielectric layers. The intermediate dielectric layer is designed with a different average pore area occupancy percentage compared to the outer dielectric layers. This asymmetric structure creates an uneven crack propagation path, preventing cracks from easily reaching internal electrode layers while maintaining controlled manufacturing precision.
3Ease of manufacture
If dielectric layers have high porosity, then ease of manufacture is improved, but crack propagation to internal electrode layers is more likely
Solution Approach 1:
The patent applies local quality by varying the porosity characteristics across different dielectric layers. The intermediate dielectric layer has a different average pore area occupancy percentage compared to the outer layers, creating localized regions with different mechanical properties. This gradient structure provides crack resistance while maintaining overall manufacturing ease.
Data Source
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AI summary
Provided is a multilayer ceramic capacitor in which a crack does not reach an internal electrode layer and fatal defects that may cause dielectric breakdown can be suppressed. This multilayer ceramic capacitor comprises: a multilayer body 12 which comprises a plurality of stacked dielectric layers 14; a first internal electrode layer 16a which is exposed in a first end surface 12e and a second internal electrode layer 16b which is exposed in a second end surface 12f, the internal electrode layers being disposed on the plurality of dielectric layers; and a first external electrode 30a and a second external electrode 30b. The multilayer body 12 has an internal layer part to which a plurality of first internal electrode layers 16a and a second internal electrode layer 16b are opposed. The dielectric layers 14 contain voids, and the voids are segregated in the dielectric layers 14. The dielectric layers 14 include a plurality of void-containing dielectric layers 14a, 14b and 14c which are different from each other in the area occupancy of voids (void fraction) in respective cross-sections of the dielectric layers 14.