Multilayer Ceramic Capacitor Floating Electrode Asymmetry
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Solution Overview
Problem
Multilayer ceramic capacitors with high voltage and low capacitance characteristics using internal electrode structures with floating electrodes often fail to achieve target capacitance, leading to reduced manufacturing yield and increased equivalent series resistance due to the need for additional buffer layers and misalignment of electrodes.
Innovation Solution
The design includes a ceramic body with dielectric layers, external and internal electrodes, and floating electrodes with overlapping portions of varying lengths, allowing for precise capacitance adjustment without increasing dielectric layer thickness or internal electrode count, and incorporating dummy electrodes for improved connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If floating electrodes are used to achieve high voltage and low capacitance characteristics, then voltage characteristics are improved, but capacitance control precision deteriorates
Solution Approach 1:
The patent applies local quality by creating asymmetric overlap lengths between floating electrodes and internal electrodes at different locations. Specifically, the first floating electrode has a first overlap length with the first internal electrode and a second overlap length with the second internal electrode, where these lengths are deliberately made different. This local variation in overlap geometry enables precise control of capacitance while maintaining the high voltage characteristics provided by the floating electrode structure.
Solution Approach 2:
The patent employs asymmetry by designing the overlap portions between floating electrodes and internal electrodes to have unequal lengths. The first overlap length and second overlap length are intentionally made asymmetric, which allows for fine-tuning of the capacitance value. This asymmetric configuration provides an additional degree of freedom for capacitance control without compromising the voltage blocking capability of the floating electrode structure.
2Adaptability or versatility
If buffer layers are added between floating electrodes and internal electrodes, then capacitance adjustment is enabled, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by varying the overlap lengths between floating electrodes and internal electrodes to control capacitance. Instead of adding buffer layers, the invention changes the geometric parameters (overlap lengths) of the existing electrode structure. By adjusting the first and second overlap lengths independently, the capacitance can be precisely controlled while avoiding the complexity of additional buffer layer structures.
Solution Approach 2:
The patent transitions from controlling capacitance through vertical buffer layer insertion to controlling it through horizontal overlap length variation. This dimensional shift allows capacitance adjustment by modifying the lateral extent of electrode overlaps rather than adding vertical layers, thereby simplifying the overall device structure while maintaining capacitance tunability.
3Quantity of substance
If the number of internal electrodes is increased to achieve target capacitance, then capacitance is improved, but equivalent series resistance increases
Solution Approach 1:
The patent changes the geometric parameters of the electrode overlaps to control capacitance. By adjusting the overlap lengths between floating and internal electrodes, the desired capacitance value is achieved without increasing the number of internal electrodes. This parameter-based control method maintains the original electrode count, thereby preserving good conductivity and low equivalent series resistance while achieving the target capacitance.
Data Source
AI summary
A multilayer ceramic capacitor may include: a ceramic body; first and second external electrodes; first and second internal electrodes connected to the first and second external electrodes, respectively; first floating electrodes having both end portions overlapped with portions of the first and second internal electrodes, respectively; and at least one second floating electrode shifted with respect to the first floating electrodes in a length direction of the ceramic body. The lengths of portions of the first and second floating electrodes overlapped with the portions of the first internal electrodes may be different from those of portions of the first and second floating electrodes overlapped with the portions of the second internal electrodes.