Multilayer Ceramic Capacitor Moisture Resistance via Localized Density
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in maintaining moisture resistance as they are miniaturized and capacitance increased, leading to reduced distance from internal electrode edges to the surface, making them susceptible to moisture ingress.
Innovation Solution
A multilayer ceramic capacitor design with specific mole ratios of elements like Ba, Mg, Mn, and rare-earth elements in perovskite compounds in different regions, increasing ceramic layer density to prevent moisture entry, and featuring external electrodes connected to internal electrodes on the surface, with defined dimensions and thicknesses of dielectric and internal electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the area of internal electrodes is increased to increase capacitance, then capacitance is improved, but the distance from the edge of the internal electrode to the surface of the multilayer ceramic capacitor is reduced, making moisture resistance deteriorate
Solution Approach 1:
The patent applies local quality by creating regions with different perovskite compound compositions in specific areas. The first and second regions (between internal electrodes and side surfaces) have a perovskite compound with a lower mole ratio of protective elements to Ti compared to the third and fourth regions (between dielectric ceramic layers and side surfaces). This localized compositional differentiation creates higher density in the outer regions to specifically address moisture resistance at critical entry points while preserving capacitance in the internal electrode areas.
Solution Approach 2:
The patent implements parameter changes by controlling the mole ratio of at least one element (Ba, Mg, Mn, or rare-earth element) to Ti in the perovskite compound. By adjusting this compositional parameter across different regions, the patent achieves varying densities - with the first and second regions having lower mole ratios that result in higher density, thereby preventing moisture entry while maintaining the electrical performance required for capacitance.
2Volume of moving object
If the multilayer ceramic capacitor is reduced in size to meet miniaturization requirements, then the size is reduced, but the distance from internal electrode edges to the surface is reduced, causing moisture resistance to deteriorate
Solution Approach 1:
The patent applies local quality by creating regions with different perovskite compound compositions in specific areas. The first and second regions (between internal electrodes and side surfaces) have a perovskite compound with a lower mole ratio of protective elements to Ti compared to the third and fourth regions (between dielectric ceramic layers and side surfaces). This localized compositional differentiation creates higher density in the outer regions to specifically address moisture resistance at critical entry points while preserving capacitance in the internal electrode areas.
Solution Approach 2:
The patent uses composite materials by incorporating a perovskite compound containing Ba and Ti with at least one element selected from Ba, Mg, Mn, and rare-earth elements. This composite approach allows for tailored regional compositions that optimize both moisture resistance and electrical performance in the miniaturized structure.
Data Source
AI summary
A multilayer ceramic capacitor with improved moisture resistance includes a laminate in which dielectric ceramic layers and internal electrodes are alternately stacked, and a pair of external electrodes provided on corresponding outer portions of the laminate. Each dielectric ceramic layer positioned between the internal electrodes, a first region positioned between the internal electrode and a first side surface in a width direction, and a second region positioned between the internal electrode and a second side surface, contains a perovskite compound containing Ba and Ti, and at least one element selected from a group consisting of Ba, Mg, Mn and a rare-earth element. Relationships S1<Sa and S2<Sa are satisfied, where mole ratios of the at least one element to Ti of the dielectric ceramic layer, the first region, and the second region, are respectively designated as Sa, S1, and S2, respectively.