Multilayer Ceramic Capacitor Electrode Coverage for Moisture Resistance
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Solution Overview
Problem
Conventional multilayer ceramic capacitors face issues with reduced moisture resistance reliability and electrostatic capacitance due to decreased internal electrode coverage, leading to increased risk of moisture infiltration and reduced adhesion between dielectric and electrode layers.
Innovation Solution
The multilayer ceramic capacitor design features a structure with varying internal electrode coverage, where the coverage is higher in the outer effective layer portion to prevent moisture infiltration and higher in the inner effective layer portion to enhance adhesion, thereby improving moisture resistance and electrostatic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the internal electrode paste is pressed during lamination, then the dielectric ceramic sheets are bonded together to form the multilayer structure, but the metal particles in the internal electrode paste flow and gather at one point, causing interruption of the internal electrode and decreased coverage
Solution Approach 1:
The patent applies different internal electrode paste formulations to different regions of the dielectric ceramic sheet. Specifically, the paste in the end regions (where coverage is critical) has different metal particle characteristics compared to the paste in the central regions, allowing local optimization of both adhesion and coverage
Solution Approach 2:
The patent changes the parameters of the internal electrode paste, specifically controlling the average particle diameter and particle size distribution of metal particles. By adjusting these parameters, the paste maintains adequate coverage after pressing while ensuring proper adhesion between layers
2Ease of manufacture
If the coverage of internal electrode with respect to dielectric ceramic is reduced at the end of the internal electrode, then the manufacturing process becomes simpler, but the risk of moisture infiltration increases and moisture resistance reliability degrades
Solution Approach 1:
The patent implements local quality by using internal electrode paste with different metal particle characteristics in the end regions compared to the central regions. This ensures high coverage at the ends where moisture infiltration risk is highest, while maintaining adequate coverage in the center, thus improving moisture resistance reliability without significantly complicating the manufacturing process
3Quantity of substance
If the coverage of internal electrode with respect to dielectric ceramic is reduced, then the manufacturing cost may be reduced, but the acquired electrostatic capacitance of the multilayer ceramic capacitor decreases
Solution Approach 1:
The patent changes the parameters of the internal electrode paste, specifically the metal particle size distribution and composition, to optimize coverage. This allows maintaining adequate electrostatic capacitance by ensuring sufficient metal particle coverage in critical regions while controlling overall material usage
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including laminated dielectric layers, first and second main surfaces, first and second end surfaces, and first and second side surfaces, first and second internal electrode layers on the dielectric layers and respectively exposed to the first and second end surfaces, and first and second external electrodes respectively on the first and second end surfaces. The multilayer body includes an effective layer portion in which the first and second internal electrode layers are opposite to each other, the effective layer portion includes inner and outer effective layer portions, and a coverage of the first and second internal electrode layers with respect to the dielectric layer in the outer effective layer portion is larger than a coverage of the first and second internal electrode layers with respect to the dielectric layer located in the inner effective layer portion.