Conductive Resin Layer Thickness Gradient for Moisture Gas Emission

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Solution Overview

Problem

The conductive resin layer in electronic components can absorb moisture, leading to volume expansion and stress, which may cause cracking and peeling off during solder-mounting on electronic devices, due to gasification of absorbed moisture without a reliable emission path.

Innovation Solution

The conductive resin layer is configured with varying thickness regions, where the second region has a maximum thickness greater than the first region, allowing gas generated from moisture absorption to reach and be emitted through a gap between the plating layer and the element body, reducing stress on the resin layer, and additional regions with smaller thicknesses to minimize moisture absorption and gas generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the conductive resin layer continuously covers the end surface and principal surface, then the external electrode structure is improved, but moisture absorption leads to gasification and peeling off during solder-mounting

Engineering Contradiction:

Improvestructural integrity of external electrodeVSAvoidpeeling resistance of conductive resin layer

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The conductive resin layer is divided into multiple regions with different thicknesses: a first region on the end surface and a second region on the principal surface. This segmentation allows different parts of the resin layer to serve different functions - the thinner first region allows gas escape while the thicker second region provides coverage and conductivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention extracts the harmful gas generated from moisture absorption and redirects it to escape through the gap between the plating layer and element body. By creating a thickness difference, the gas is channeled away from the critical interface between the conductive resin layer and element body, preventing peeling.

Inventive Principle:

Principle #2Taking out (Extraction)

2Strength

If the resin in the conductive resin layer absorbs moisture, then the resin becomes more flexible, but volume expansion occurs causing stress and cracking

Engineering Contradiction:

Improveflexibility of resinVSAvoidinternal stress from volume expansion

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The invention converts the harmful effect of moisture absorption (which causes volume expansion and stress) into a beneficial outcome. By allowing controlled gas escape through the thickness variation, the harmful gasification process is harnessed to relieve internal stress without causing damage, turning a defect into a protective mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If the plating layer is disposed to cover the conductive resin layer, then the external electrode conductivity is improved, but a gap forms between the plating layer and element body which may allow moisture ingress

Engineering Contradiction:

Improveelectrical conductivity of external electrodeVSAvoidmoisture absorption by resin

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The thickness difference in the conductive resin layer acts as an intermediary mechanism. It creates a controlled path for gas escape that mediates between the plating layer and element body, allowing gas to escape through the gap without allowing moisture to ingress. The resin thickness gradient serves as a buffer that manages the interaction between these components.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 configuration effectively controls the peeling off of the conductive resin layer by ensuring gas emission outside the external electrode, reducing stress and absorption, thereby enhancing the reliability of the electronic component.

Implementation Method 1

The conductive resin layer generally contains a resin and electrically-conductive particles. The resin tends to absorb moisture.

Methodology Applied

Scientific EffectMoisture absorption: Absorption (physical)

Implementation Method 2

In a case in which the electronic component is solder-mounted on an electronic device, the moisture absorbed by the resin may be gasified so that volume expansion may occur.

Methodology Applied

Scientific EffectGasification: Evaporation

Implementation Method 3

The gas generated from the moisture reaches the gap between the end edge of the plating layer and the element body, and the gas is emitted outside the external electrode through the gap.

Methodology Applied

Scientific EffectGas movement through thickness gradient: Diffusion

Data Source

PatentUS11217391B2Electronic component

Publication Date: 2022.01.04 TDK CORP

AI summary

An electronic component includes an element body and an external electrode disposed on the element body. The element body includes a principal surface arranged to constitute a mounting surface and an end surface adjacent to the principal surface. The external electrode includes a conductive resin layer disposed to continuously cover a part of the principal surface and a part of the end surface, and a plating layer covering the conductive resin layer. The conductive resin layer includes a first region positioned on the end surface and a second region positioned on the principal surface. A maximum thickness of the second region is larger than a maximum thickness of the first region.