Multilayer Ceramic Capacitor Gap Structure for Moisture Blocking

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Solution Overview

Problem

Multilayer ceramic capacitors face moisture ingress issues, leading to deterioration of electric characteristics due to the penetration of moisture from external electrodes to internal electrode layers.

Innovation Solution

The design incorporates a multilayer body with alternately arranged first and second internal electrode layers, connected to external electrodes with gaps, and includes conductor portions in outer layer portions that pressurize the inner layer portion towards the middle, enhancing moisture resistance by preventing moisture penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If external electrodes are provided on end surfaces for electrical connection, then electrical functionality is achieved, but moisture ingress pathways are created that lead to deterioration of electric characteristics

Engineering Contradiction:

Improveelectrical characteristic stabilityVSAvoidmoisture ingress

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Conductor portions are introduced as intermediary elements between the external electrodes and the internal electrode layers. These conductor portions extend into the end gap portions and pressurize the inner layer portion, creating a protective barrier that prevents moisture from reaching the internal electrode layers while maintaining electrical connectivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The conductor portions are positioned in advance to counteract the harmful effect of moisture ingress. By extending into the end gap portions and pressurizing the inner layer portion before moisture can penetrate, the conductor portions create a preliminary defensive action that blocks moisture pathways.

Inventive Principle:

Principle #9Preliminary anti-action

2Volume of moving object

If internal electrode layers are arranged close to end surfaces for compact design, then device size is reduced, but moisture penetration to internal electrodes increases

Engineering Contradiction:

Improvecapacitor sizeVSAvoidmoisture resistance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

Conductor portions serve as intermediary protective elements that extend into the end gap portions where internal electrode layers are located. These conductor portions pressurize the inner layer portion, creating a protective barrier that allows compact arrangement of internal electrodes while preventing moisture penetration.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Length of moving object

If end gap portions are minimized for compact structure, then device dimensions are reduced, but moisture ingress pathways are shortened allowing faster moisture penetration

Engineering Contradiction:

Improveend gap lengthVSAvoidmoisture penetration speed

Core Design Contradiction:

Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

Conductor portions are positioned in the end gap portions to act as intermediary protective elements. Even when end gap portions are minimized, the conductor portions extend into these gaps and pressurize the inner layer portion, creating a protective barrier that slows and prevents moisture penetration despite the reduced gap length.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If conductor portions extend deeply into end gap portions for better protection, then moisture resistance improves, but manufacturing complexity increases

Engineering Contradiction:

Improvemoisture resistanceVSAvoidconductor portion configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The conductor portions are segmented into multiple conductor layers stacked in the stacking direction. This segmentation allows the conductor portions to achieve effective protection against moisture ingress while maintaining a manageable and manufacturable structure, as each layer can be formed independently through standard printing processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The conductor portions extend partially into the end gap portions - not fully throughout the entire gap length, but sufficiently to pressurize the inner layer portion and block moisture pathways. This partial extension achieves effective protection while avoiding excessive complexity in the conductor portion configuration.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS11894198B2Multilayer ceramic capacitor

Publication Date: 2024.02.06 MURATA MFG CO LTD

AI summary

A multilayer ceramic capacitor includes a multilayer body including dielectric layers and internal electrode layers stacked together, and external electrodes. The multilayer body includes an inner layer portion and outer layer portions in a stacking direction, and an electrode opposing portion and gap portions in a length direction. The multilayer body further includes conductor portions in the two outer layer portions in the gap portions, and each includes conductor layers stacked in the stacking direction. One of that conductor layers that is closest to a middle in the stacking direction of the multilayer body is closer to the middle in the stacking direction of the multilayer body than another of the internal electrode layers closest in the stacking direction to a main surface of the multilayer body.