Multilayer Ceramic Capacitor CR Product Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multilayer ceramic capacitors face a challenge in improving the CR product (capacitance times insulation resistance) without compromising capacitance, as reducing dielectric layer thickness to increase capacitance often decreases insulation resistance, and accurately controlling grain size and volume ratio in existing methods is difficult.
Innovation Solution
The multilayer ceramic capacitor design incorporates multiple internal electrode layers with dielectric layers, forming specific capacitance distributions with distinct low-capacitance, high-capacitance, and variable-capacitance areas, optimizing the arrangement of unit capacitors to enhance the CR product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the dielectric layers is reduced to increase capacitance, then the capacitance increases, but the insulation resistance decreases
Solution Approach 1:
The capacitive part is divided into multiple unit capacitors (first low-capacitance area, high-capacitance area, second low-capacitance area) with different capacitance characteristics. This segmentation allows the capacitor to achieve high overall capacitance while maintaining adequate insulation resistance through the distributed structure, where not all regions operate at the same high-capacitance/thin-dielectric state
Solution Approach 2:
Different regions of the capacitive part have different capacitance characteristics - the first and second low-capacitance areas have smaller unit capacitances compared to the high-capacitance area. This local quality variation allows optimization of insulation resistance in critical regions while maintaining high capacitance in other regions, resolving the contradiction between overall capacitance and local insulation resistance
2Reliability
If the grain size and volume ratio of crystal grains are limited to prevent CR product drop, then the CR product can be maintained, but accurate control is difficult in manufacturing
Solution Approach 1:
Instead of controlling grain size and volume ratio (which are difficult to control in manufacturing), the invention changes the approach to controlling capacitance distribution by adjusting the number and arrangement of unit capacitors with different capacitance values. This parameter change from microstructural control to macrostructural control makes the manufacturing process more feasible while achieving the same goal of maintaining CR product
Data Source
AI summary
In some embodiments, a multilayer ceramic capacitor 10 has 23 unit capacitors UC1 to UC23, where these 23 unit capacitors UC1 to UC23 constitute: a first low-capacitance area LA1 constituted by three unit capacitors UC1 to UC3; a high-capacitance area HA constituted by 17 unit capacitors UC4 to UC20 whose unit capacitance is greater than that of the three unit capacitors UC1 to UC3; a second low-capacitance area LA2 constituted by three unit capacitors UC21 to UC23 whose unit capacitance is smaller than that of the 17 unit capacitors UC4 to UC20; a first variable-capacitance part which is present between the first low-capacitance area LA1 and high-capacitance area HA, and which includes the two adjacent unit capacitors UC3, UC4; and a second variable-capacitance part which is present between the high-capacitance area HA and second low-capacitance area LA2, and which includes the two adjacent unit capacitors UC20, UC21.