Multilayer Ceramic Capacitor Segmented Conductor Design
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Solution Overview
Problem
High voltage capacitor designs face a trade-off between high capacitance and low flashover, with existing solutions either compromising capacitance or introducing thermal mismatch issues and increased costs.
Innovation Solution
A multilayer ceramic capacitor design featuring internal conductors with alternating polarity and external terminations with side extensions, where the internal conductors have a bulk region and a secondary region with reduced width, allowing for increased overlap area and reduced separation distance to minimize flashover without thermal mismatch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If serial capacitor design is used to increase voltage capability, then voltage rating is improved, but effective capacitance is significantly lowered
Solution Approach 1:
The internal conductor is segmented into a bulk region and a secondary region with different widths. The secondary region has reduced width to create spacing from opposite polarity electrodes, preventing flashover while the bulk region maintains large overlap area for high capacitance. This segmentation allows the single capacitor structure to achieve both high voltage capability and high capacitance without requiring serial connection.
2Quantity of substance
If overlap area is increased to improve capacitance, then capacitance is improved, but flashover risk increases
Solution Approach 1:
Different regions of the internal conductor are given different local qualities: the bulk region has large width to maximize overlap area and capacitance, while the secondary region has reduced width to create safe spacing from opposite polarity electrodes and prevent flashover. This local differentiation allows the structure to simultaneously achieve high capacitance and low flashover risk.
3Object-affected harmful factors
If different dielectric materials are used to reduce flashover, then flashover is decreased, but thermal mismatch and stress are introduced
Solution Approach 1:
The solution extracts the flashover prevention function from the dielectric material and relocates it to the conductor geometry. By shaping the internal conductor with a secondary region that provides spacing from opposite polarity electrodes, the patent eliminates the need for additional dielectric materials with different thermal properties, thereby preventing flashover without introducing thermal mismatch or stress.
4Object-affected harmful factors
If leaded capacitor design with epoxy coating is used to reduce arc over, then arc over is reduced, but automated surface mount assembly is not possible and cost increases
Solution Approach 1:
The capacitor structure provides self-service flashover protection through its own geometry. The secondary region of the internal conductor inherently creates spacing that prevents flashover without requiring external protective coatings or lead structures. This eliminates the need for epoxy coating and lead attachments, enabling direct automated surface mount assembly while maintaining arc over protection.
Data Source
AI summary
A method for making multilayer ceramic capacitors is described with high voltage capability without the need of coating the part to resist surface arc-over. One design combines a high overlap area for higher capacitance whilst retaining a high voltage capability. A variation of this design has increased voltage capability over this design as well as another described in the prior art although overlap area and subsequently capacitance is lowered in this case.