Multilayer Ceramic Capacitor Internal Electrode Shielding
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in achieving high voltage breakdown and resistance to arc-over, with existing solutions either being costly or incompatible with circuit board processes, and often compromising capacitance or being prone to corrosion.
Innovation Solution
A multilayer ceramic capacitor design featuring internal electrode shields and a coating to enhance breakdown voltage, with alternating electrode configurations and side shields to prevent arc-over, allowing for higher voltage handling and miniaturization while maintaining capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a series design with floating electrodes is used to reduce internal voltage, then voltage breakdown resistance is improved, but effective overlap area is significantly reduced
Solution Approach 1:
The capacitor is divided into multiple series-connected voltage holding sections, each with its own floating electrode and dielectric layer. This segmentation allows the total voltage to be distributed across multiple lower-voltage sections, improving voltage breakdown resistance while maintaining adequate overlap area in each section.
Solution Approach 2:
Electrode shields are nested within the capacitor structure, positioned between the electrodes and the external environment. These shields extend partially into the active region, providing additional voltage protection without requiring a complete redesign of the electrode configuration, thus preserving effective overlap area.
2Ease of manufacture
If exposed electrodes are used to maintain capacitance, then manufacturing simplicity is improved, but resistance to arc-over and corrosion is worsened
Solution Approach 1:
Electrode shields act as intermediary elements between the exposed electrodes and the external environment. These shields prevent direct exposure of the electrodes to corrosive environments and arc-over conditions, while still allowing the capacitor to be manufactured using standard processes without complex coating or sealing steps.
3Ease of manufacture
If standard capacitor design is used to maintain high capacitance, then manufacturing simplicity is improved, but voltage breakdown resistance is reduced
Solution Approach 1:
The capacitor structure is segmented into multiple voltage holding sections connected in series, with each section containing electrodes of opposite polarity. This segmentation enables the capacitor to handle higher voltages by distributing the electrical stress across multiple lower-voltage sections, while still using standard manufacturing processes.
Solution Approach 2:
The capacitor employs a composite structure combining dielectric layers, electrode layers, and electrode shields in specific configurations. This composite design achieves both high voltage breakdown resistance and high capacitance by optimizing the interaction between different material layers and their geometric arrangements.
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 design achieves significant improvements in voltage breakdown and resistance to arc-over, enabling the use of capacitors in high-voltage applications with reduced size and manufacturing costs, and improved reliability by minimizing unwanted disruptions.
Implementation Method 1
a coating on the ceramic capacitor body to assist in increasing breakdown voltage
Implementation Method 2
a plurality of internal electrode shields within the ceramic capacitor body to thereby assist in providing resistance to arc-over
Data Source
AI summary
A capacitor includes a ceramic capacitor body having opposite ends and comprised of a plurality of electrode layers and dielectric layers and first and second external terminals attached to the ceramic capacitor body. The internal active electrodes within the ceramic capacitor body are configured in an alternating manner. Internal electrode shields within the ceramic capacitor body are used to assist in providing resistance to arc-over. The shields may include a top internal electrode shield and an opposite bottom internal electrode shield wherein the top internal electrode shield and the opposite bottom internal electrode shield are on opposite sides of the plurality of internal active electrodes and each internal electrode shield extends inwardly to or beyond a corresponding external terminal to thereby provide shielding. Side shields are used. The capacitor provides improved resistance to arc-over, high voltage breakdown in air, and allows for small case size. To further increase voltage breakdown, a coating on the ceramic capacitor may be used.