Multilayer Ceramic Capacitor Particle Size Gradient
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in increasing capacitance while maintaining reliability, as thinner dielectric layers and larger particle sizes lead to decreased insulation resistance and withstand voltage, requiring precise structural control of dielectric particle sizes.
Innovation Solution
A multilayer ceramic electronic component with a specific distribution of dielectric particle sizes, where the average diameter in the outer peripheral portion is larger than in the center portion, and a manufacturing method involving ceramic green sheets with a perovskite structure and controlled oxygen partial pressure firing, to enhance withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the dielectric layer is made thinner and the particle size is increased to increase capacitance, then the capacitance increases, but the insulation resistance and withstand voltage decrease
Solution Approach 1:
The patent applies local quality by creating different particle size distributions in different regions of the dielectric layer. The center portion has smaller particles (average diameter d) while the outer peripheral portion has larger particles (average diameter D), with D/d ≥ 1.05. This regional differentiation allows the center to maintain high insulation resistance while the outer regions contribute to higher capacitance, resolving the contradiction between capacitance increase and reliability maintenance.
2Quantity of substance
If the dielectric layer is made thinner to increase capacitance, then the capacitance increases, but the number of particles per layer decreases leading to reliability deterioration
Solution Approach 1:
By making the dielectric layer thinner overall but concentrating smaller particles in the center portion, the patent maintains adequate particle density in the critical center region for insulation resistance, while the thinner outer regions still contribute to capacitance. The controlled particle size distribution compensates for the reduced layer thickness.
3Quantity of substance
If larger dielectric particles are used in the center portion to improve capacitance, then the capacitance increases, but the withstand voltage becomes low
Solution Approach 1:
The patent inverts the conventional approach by making the center portion particles smaller than the outer peripheral particles. This inverted particle size distribution (D/d ≥ 1.05) ensures that the center, which determines withstand voltage, has smaller particles for higher insulation resistance, while the outer regions have larger particles that contribute to capacitance without compromising the center's electrical performance.
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
The solution effectively improves the withstand voltage of multilayer ceramic capacitors by maintaining adequate capacitance and reliability through a controlled particle size distribution and optimized manufacturing process.
Implementation Method 1
a capacitor section where the internal electrode layers electrically connected to one of the pair of external electrodes and the internal electrode layers electrically connected to another of the pair of external electrodes face each other
Implementation Method 2
the plurality of dielectric layers may have a perovskite structure represented by the general formula ABO3 with an A/B ratio being 0.90 or more and 0.98 or less
Implementation Method 3
firing the laminate at an oxygen partial pressure of 10-5 to 10-8 atm and a temperature range of 1150° C. to 1250° C. to obtain a main body
Data Source
AI summary
A multilayer ceramic electronic component includes a main body including a laminated portion in which a plurality of dielectric layers and a plurality of internal electrode layers are laminated; and a pair of external electrodes provided on surfaces of the main body, wherein in a capacitor section where the internal electrode layers electrically connected to one of the pair of external electrodes and the internal electrode layers electrically connected to another of the pair of external electrodes face each other, an average diameter d of dielectric particles in the dielectric layers in a center portion is smaller than an average diameter D of the dielectric particles in the dielectric layers in at least a part of an outer peripheral portion outside the center portion.