Multilayer Ceramic Capacitor Grain Layout for Capacitance and Reliability
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in achieving improved effective capacitance while maintaining reliability, as suppressing grain growth of dielectric particles to enhance capacitance leads to reduced reliability due to retarded sintering and solid solution of rare earth elements.
Innovation Solution
The multilayer ceramic capacitor is sectioned into specific regions with varying dielectric particle sizes, including core-shell and homogeneous solid solution particles, and is structured to include side margin portions that promote grain growth and solid solution of rare earth elements, enhancing reliability and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grain growth of dielectric particles is suppressed to enhance effective capacitance, then effective capacitance is improved, but reliability deteriorates due to retarded sintering and solid solution of rare earth elements
Solution Approach 1:
The patent applies local quality by creating distinct regions within the dielectric layer with different particle size characteristics. The first region contains dielectric particles with a first average particle size, while the second region contains dielectric particles with a second average particle size that is larger than the first. This spatial differentiation allows the smaller particles in the first region to provide high capacitance while the larger particles in the second region promote sintering and solid solution formation, thereby simultaneously achieving high effective capacitance and reliability without uniform grain growth suppression throughout the entire structure.
2Productivity
If uniform small particle size is maintained throughout the dielectric layer, then effective capacitance increases, but sintering progress and rare earth element solid solution are retarded
Solution Approach 1:
The patent implements local quality by establishing a non-uniform particle size distribution across the dielectric layer thickness. By concentrating smaller dielectric particles in regions where capacitance contribution is prioritized and larger dielectric particles in regions where sintering and solid solution are critical, the structure achieves both high effective capacitance and adequate sintering progress. The larger particles in the second region act as sintering promoters while the smaller particles in the first region maximize capacitance, resolving the contradiction between uniform small particle size and sintering progress.
3Productivity
If dielectric particle size is reduced to enhance capacitance, then effective capacitance improves, but insulation resistance deterioration increases
Solution Approach 1:
The patent applies local quality by creating a bimodal particle size distribution where smaller dielectric particles dominate in capacitance-critical regions while larger dielectric particles are positioned in regions where insulation stability is prioritized. The larger particles in the second region provide better sintering and solid solution formation, which enhances grain boundary properties and reduces insulation resistance deterioration, while the smaller particles in the first region maintain high effective capacitance. This spatial separation of particle size functions resolves the contradiction between reduced particle size for capacitance and insulation resistance maintenance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This structure improves the reliability and effective capacitance of the multilayer ceramic capacitor by optimizing dielectric particle distribution and promoting grain growth in critical regions, thereby extending high-temperature load life and reducing insulation resistance deterioration.
Implementation Method 1
the progress of sintering of the dielectric particles to suppress the grain growth of the dielectric particles
Implementation Method 2
the progress of the solid solution of a rare earth element is also retarded
Data Source
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AI summary
The present invention provides a multilayer ceramic capacitor capable of enhancing reliability while increasing effective capacity. A multilayer ceramic capacitor (100) comprising a laminate (6) including a plurality of dielectric layers (2) and a plurality of internal electrode layers (4) laminated in the thickness direction, and a pair of external electrodes, wherein an inner layer part (16) of the laminate (6) comprises a central region (16c) in the widthwise center, a first side margin adjacent region (16a) adjacent to a first side margin part (20a), and a second side margin adjacent region (16b) adjacent to a second side margin part (20b). The area equivalent diameter D50 of dielectric particles in dielectric layers of the first side margin adjacent region (16a) and the second side margin adjacent region (16b) is larger than the area equivalent diameter D50 of dielectric particles in the dielectric layer of the central region (16c).