Multilayer Ceramic Capacitor Dummy Layers Acoustic Noise

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Solution Overview

Problem

Multilayer ceramic capacitors generate acoustic noise due to vibrations caused by the piezoelectric phenomenon when a voltage is applied, leading to listener discomfort.

Innovation Solution

A multilayer ceramic electronic component is designed with active layers and dummy layers alternately stacked within a ceramic body, where the dummy layers have a thickness 1.5 times that of the dielectric layers, to cancel out expansion and contraction stress, reducing vibrations and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a multilayer ceramic capacitor is designed with only active layers containing internal electrodes, then the capacitance function is achieved, but acoustic noise is generated due to piezoelectric vibrations

Engineering Contradiction:

Improvecapacitance functionVSAvoidacoustic noise

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The ceramic body is segmented into alternating active layers and dummy layers. The active layers contain internal electrodes and provide capacitance function, while the dummy layers contain only dielectric material and serve to cancel piezoelectric stress. This segmentation allows the capacitor to maintain its electrical function while reducing acoustic noise through stress cancellation between adjacent layers with opposite polarization directions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The dummy layers act as intermediary elements between the active layers. These intermediate layers do not contribute directly to capacitance but serve as stress-canceling elements that counteract the piezoelectric vibrations generated by the active layers, thereby reducing acoustic noise without affecting the electrical performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If dummy layers are added to reduce acoustic noise, then vibrations are suppressed, but the device structure becomes more complex

Engineering Contradiction:

ImprovevibrationsVSAvoidlayer structure

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The manufacturing process merges the formation of active layers and dummy layers into a single integrated structure. Both layer types are formed using the same dielectric material composition and are stacked alternately in a unified ceramic body, simplifying the overall manufacturing process despite the increased structural complexity of having alternating layers.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The thickness of the dummy layers is optimized to be substantially equal to or greater than that of the active layers to achieve effective stress cancellation. By adjusting this critical parameter, the patent achieves vibration suppression while maintaining a relatively simple alternating layer structure that can be manufactured using standard multilayer ceramic processing techniques.

Inventive Principle:

Principle #35Parameter changes

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

The solution effectively reduces acoustic noise by counteracting the stress generated in active layers with that in dummy layers, minimizing vibrations transferred to the board.

Implementation Method 1

Since the dielectric layer has piezoelectric and electrostrictive properties, a piezoelectric phenomenon occurs between the internal electrodes when a direct current (DC) or alternating current (AC) voltage is applied to the multilayer ceramic capacitor, such that vibrations may be generated

Methodology Applied

Scientific EffectPiezoelectric phenomenon: Piezoelectric Effect

Implementation Method 2

Methodology Applied

Scientific EffectElectrostriction:

Data Source

PatentUS9460851B2Multilayer ceramic electronic component and board having the same

Publication Date: 2016.10.04 SAMSUNG ELECTRO MECHANICS CO LTD

AI summary

A multilayer ceramic electronic component may include a ceramic body having a plurality of dielectric layers stacked in the ceramic body; a plurality of active layers including first and second internal electrodes disposed to be alternately exposed to the end surfaces of the ceramic body with the dielectric layers interposed between the first and second internal electrodes; and dummy layers disposed between the active layers.