Monolithic Ceramic Capacitor Terminal Electrode ESR Control
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Solution Overview
Problem
Existing monolithic ceramic capacitors face challenges in maintaining reliability and size reduction while incorporating a resistance component to control equivalent series resistance (ESR), as previous methods either suffer from reduced reliability due to moisture intrusion or increased size from thick film layers.
Innovation Solution
The LW-reverse-type monolithic ceramic capacitor features external terminal electrodes with a layered structure, including a first layer with a glass component and compound oxide, a second layer of metal, and a third layer formed by plating, where the edge of the wrap-around portion of the first layer remains exposed, ensuring consistent dimensions and reduced size without compromising reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a thick film structure is used to control ESR, then ESR is reduced, but the capacitor size increases and reliability decreases due to moisture intrusion
Solution Approach 1:
The external terminal electrode is divided into multiple layers (first layer with glass component and compound oxide, second layer with metal, third layer formed by plating) instead of using a single thick film structure. This segmentation allows each layer to perform specific functions: the first layer controls ESR through its resistance properties, while subsequent layers provide protection and conductivity, thereby reducing ESR without compromising reliability or increasing overall size.
Solution Approach 2:
The first layer of the external terminal electrode is formed as a composite material containing both a glass component and a compound oxide. This composite structure provides the desired resistance characteristics to control ESR while maintaining structural integrity and reliability. The glass component contributes to the composite's resistance properties and structural stability, preventing moisture intrusion.
2Loss of energy
If a thick film structure is used to control ESR, then ESR is reduced, but the capacitor size increases
Solution Approach 1:
The external terminal electrode is divided into multiple thin layers instead of using a single thick film. The first layer (with glass component and compound oxide) provides ESR control, while the second and third layers provide additional functionality. This segmentation allows for effective ESR reduction without requiring a large overall film thickness, thereby maintaining compact capacitor dimensions.
3Ease of operation
If the wrap-around portion dimensions vary, then mountability is poor, but maintaining consistent dimensions may require thicker films
Solution Approach 1:
The external terminal electrode is segmented into multiple layers with the first layer forming the wrap-around portion. This segmentation allows the wrap-around dimensions to be precisely controlled by the first layer's formation process, ensuring consistent dimensions for good mountability. The subsequent layers are formed based on this established structure, preventing size increase while maintaining mountability.
Solution Approach 2:
The dimensions of the wrap-around portion are controlled by adjusting parameters of the first layer formation process. By optimizing the thickness and material composition of the first layer, consistent wrap-around dimensions are achieved, ensuring good mountability without requiring increased overall film thickness that would enlarge the capacitor.
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
This structure enhances mountability and reliability by preventing moisture intrusion while allowing for a decrease in capacitor size, maintaining a desired ESR through a controlled current path and material selection.
Implementation Method 1
a first layer having a wrap-around portion extending from one of the end surfaces to the principal surfaces and the side surfaces, and including a glass component and a compound oxide that reacts with the Ni or the Ni alloy
Implementation Method 2
a first layer having a wrap-around portion extending from one of the end surfaces to the principal surfaces and the side surfaces, and including a glass component and a compound oxide that reacts with the Ni or the Ni alloy
Implementation Method 3
a third layer covering the edge of the wrap-around portion of the first layer and the second layer, and formed by plating
Data Source
AI summary
In an LW-reverse-type monolithic ceramic capacitor including external terminal electrodes each including a resistance component, internal electrodes include nickel or a nickel alloy, and the external terminal electrodes each include a first layer, a second layer provided on the first layer, and a third layer provided on the second layer. The first layer has a wrap-around portion extending from an end surface to principal surfaces and side surfaces of a capacitor main body, and contains a glass component and a compound oxide that reacts with Ni or the Ni alloy. The second layer covers the first layer such that the edge of the wrap-around portion of the first layer remains exposed, and contains a metal. The third layer covers the edge of the wrap-around portion of the first layer and the second layer, and is formed by plating.