Multilayer Ceramic Capacitor Lower Cover Layer Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multilayer ceramic capacitors face challenges in reducing acoustic noise while maintaining equivalent series inductance (ESL) and ensuring reliability, as increasing the thickness of the lower cover layer can lead to bending cracks and reduced capacitance and insulation resistance.
Innovation Solution
A multilayer ceramic capacitor design with a thicker lower cover layer and internal electrodes having an overlapping area, where the distance of the longitudinal margin portion from the ceramic body boundary to the overlapping area is maximized, along with specific ratios of cover layer thicknesses to prevent crack propagation and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the thickness of the lower cover layer is increased to reduce acoustic noise, then acoustic noise is reduced, but equivalent series inductance (ESL) increases
Solution Approach 1:
The lower cover layer is segmented into multiple functional zones: a first lower cover layer portion directly below the active layer with optimized thickness for acoustic noise reduction, and a second lower cover layer portion extending further down with internal electrodes. This segmentation allows different regions to serve different functions - the first portion reduces acoustic noise while the second portion maintains ESL characteristics through internal electrode configuration.
Solution Approach 2:
Different regions of the lower cover layer are given different properties and functions. The first lower cover layer portion has specific thickness characteristics optimized for acoustic noise reduction, while the second lower cover layer portion contains internal electrodes with specific overlapping area ratios optimized for ESL control. This local differentiation resolves the contradiction by allowing each region to optimize for its specific function.
2Object-affected harmful factors
If the thickness of the lower cover layer is increased to reduce acoustic noise, then acoustic noise is reduced, but bending cracks may occur causing reduced capacitance and insulation resistance
Solution Approach 1:
The lower cover layer is divided into a first portion and a second portion, with the internal electrodes specifically positioned in the second portion. This segmentation prevents bending cracks from propagating into the active layer region, as the crack path is interrupted by the structural design and material composition differences between the two portions.
Solution Approach 2:
The internal electrodes are positioned in the second lower cover layer portion with a specific overlapping area ratio (greater than 10% and not more than 90%) to create a buffer zone that absorbs and distributes stress before it can propagate to the active layer. This beforehand cushioning prevents crack propagation that would otherwise damage the capacitance-forming structures.
Data Source
AI summary
A multilayer ceramic capacitor includes a ceramic body, an active layer, dielectric layers being interposed between first internal electrodes and second internal electrodes, an upper cover layer, a lower cover layer, a first external electrode and a second external electrode covering first and second ends of the ceramic body, and the multilayer ceramic capacitor comprising a plurality of internal electrodes disposed within the lower cover layer, when a distance of a longitudinal margin portion from a boundary of a ceramic body of the plurality of internal electrodes disposed in the lower cover layer to an overlapping area is indicated as G, and widths of an upper band portion and a lower band portion of an external electrode disposed in an upper surface and a lower surface at the boundary of the ceramic body are indicated as E1 and E2, G is greater than E1 and G is greater than E2.