Multilayer Capacitor Electrode Configuration for ESL Reduction

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Solution Overview

Problem

Multilayer ceramic capacitors face challenges in maintaining satisfactory electrical characteristics and moisture resistance due to variations in installation posture and terminal electrode configurations, which affect equivalent series inductance (ESL) and insulation resistance.

Innovation Solution

The design includes specific configurations for terminal electrodes and inner electrodes, such as projecting portions and extending portions, to optimize the connection with the installation board, reduce ESL, and enhance moisture resistance by ensuring proper alignment and sealing, while maintaining large capacitance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If terminal electrodes are provided only on main surfaces, then manufacturing is simple, but ESL increases and electrical characteristics deteriorate

Engineering Contradiction:

Improveterminal electrode configurationVSAvoidelectrical characteristics

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent extends terminal electrodes from traditional main surface locations to include end surfaces, adding a dimensional aspect to electrode placement. This multi-surface configuration reduces ESL by creating shorter current paths and improving electrical characteristics without significantly complicating manufacturing processes.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If inner electrodes extend to main surfaces, then capacitance increases, but moisture resistance deteriorates

Engineering Contradiction:

ImprovecapacitanceVSAvoidmoisture resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements extending portions of inner electrodes that protrude beyond dielectric layers before final assembly, allowing for preliminary sealing actions. Conductive paste is applied to these extending portions to create sealed connections that prevent moisture ingress while maintaining the capacitance benefits of extended electrode surfaces.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Conductive paste serves as an intermediary material between the extending inner electrodes and the external environment. This paste layer provides both electrical connection and moisture sealing, resolving the contradiction between maintaining high capacitance through electrode extension and preventing moisture damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If terminal electrodes are positioned at end portions, then ESL reduces, but manufacturing precision requirements increase

Engineering Contradiction:

ImproveESLVSAvoidterminal electrode positioning

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent divides the terminal electrode structure into multiple functional segments: extending portions that protrude for connection, main body portions on dielectric layers, and end surface portions. This segmentation allows each segment to be optimized independently, reducing overall ESL while maintaining manageable manufacturing precision requirements through modular construction.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS10170247B2Multilayer capacitor and installation structure of multilayer capacitor

Publication Date: 2019.01.01 MURATA MFG CO LTD

AI summary

In a multilayer capacitor, both a minimum distance in a thickness direction between a first effective portion of a first inner electrode and a second main surface and a minimum distance in the thickness direction between a second effective portion of a second inner electrode and the second main surface are shorter than any of a dimension in the thickness direction of a first extending portion of the first inner electrode, a dimension in the thickness direction of a second extending portion of the first inner electrode and a dimension in the thickness direction of the third extending portion of the second inner electrode.