Asymmetric Multilayer Ceramic Capacitor Electrodes
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in reducing height while maintaining strength, as eliminating the third and fourth parts of external electrodes to increase capacitance and decrease size makes them susceptible to cracking under external forces.
Innovation Solution
The capacitors are designed with first and second external electrodes having differently sized parts on height-direction faces, where the reference length of one part is set to be greater than the other, distributing internal forces to prevent alignment and thus reduce cracking risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the third part and fourth part of external electrodes are eliminated to increase capacitance and decrease size, then the capacitance can be increased and the height of the capacitor body can be decreased, but the capacitor body becomes more susceptible to cracking under external forces
Solution Approach 1:
The patent applies asymmetry by making the first part and second part of each external electrode have different reference lengths. Specifically, for the first external electrode, the reference length of the first part (L1a) is set differently from the reference length of the second part (L1b), and similarly for the second external electrode (L2a ≠ L2b). This asymmetric design prevents the concentration of internal forces at aligned positions, thereby suppressing cracking while maintaining reduced height and increased capacitance.
2Length of stationary object
If the height of the capacitor body is decreased to reduce the size of electronic devices, then the height of circuit boards can be decreased, but the strength of the capacitor body is reduced making it susceptible to cracking
Solution Approach 1:
The patent resolves this contradiction by implementing asymmetric external electrode designs where the reference lengths of corresponding parts differ (L1a ≠ L1b and L2a ≠ L2b). This asymmetry distributes internal forces non-uniformly, preventing force concentration that would lead to cracking, thereby maintaining strength even when the capacitor body height is minimized for compact electronic devices.
3Quantity of substance
If each external electrode is shaped as one having no third part or fourth part (having only the first part and the second part), then the capacitance can be increased without changing the width, but the capacitor body becomes more susceptible to cracking when height is decreased
Solution Approach 1:
The patent applies asymmetry by configuring the first part and second part of each external electrode with different reference lengths (L1a ≠ L1b for the first external electrode, and L2a ≠ L2b for the second external electrode). This asymmetric configuration, combined with eliminating the third and fourth parts, increases capacitance while preventing force alignment that causes cracking, thereby maintaining reliability.
Data Source
AI summary
In an embodiment, a multilayer ceramic capacitor 10 includes: a first external electrode 12 having a first part 12a provided on one height-direction face, and a second part 12b provided on the other height-direction face, of the capacitor body 11; and a second external electrode 13 having a first part 13a provided on one height-direction face, and a second part 13b provided on the other height-direction face, of the capacitor body 11. In addition, the reference length L1a of the first part 12a, and the reference length L1b of the second part 12b, of the first external electrode 12 satisfy the relational expression “L1a>L1b,” while the reference length L2a of the first part 13a, and the reference length L2b of the second part 13b, of the second external electrode 13 satisfy the relational expression “L2a<L2b.”