Multilayer Capacitor Insulating Layer for Piezoelectric Noise Reduction

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Solution Overview

Problem

Multilayer ceramic capacitors generate acoustic noise due to piezoelectric vibrations, which causes discomfort in electronic devices, especially in voice communication products like smartphones, where low noise designs are desired.

Innovation Solution

A multilayer capacitor design featuring a capacitor body with alternately disposed internal electrodes, an insulating layer covering band portions of external electrodes, and terminal electrodes to absorb mechanical stresses and vibrations, reducing piezoelectric vibrations and acoustic noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a multilayer capacitor is used to provide compactness and high capacitance, then the capacitor achieves small size and high performance, but piezoelectric vibrations occur causing acoustic noise

Engineering Contradiction:

Improvecapacitor sizeVSAvoidacoustic noise

Core Design Contradiction:

Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

An insulating layer is introduced as an intermediary element between the internal electrodes and the external environment. This insulating layer absorbs and dampens the piezoelectric vibrations generated by the capacitor, preventing them from propagating as acoustic noise while allowing the capacitor to maintain its compact multilayer structure

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful piezoelectric vibrations into a beneficial damping effect by utilizing the insulating layer's material properties. The vibrations that would normally cause noise are instead absorbed and dissipated as minimal heat energy within the insulating material, transforming a harmful effect into a noise-reduction mechanism

Inventive Principle:

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

2Ease of manufacture

If the capacitor structure is simplified for ease of manufacture, then production cost decreases, but acoustic noise reduction effectiveness may be compromised

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidacoustic noise

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the physical and chemical parameters of the insulating layer (material composition, thickness, density) to optimize its vibration-damping properties. By adjusting these parameters, the insulating layer achieves effective noise reduction while maintaining compatibility with standard manufacturing processes for multilayer capacitors

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 design effectively reduces acoustic noise by absorbing piezoelectric vibrations through the insulating layer, enhancing long-term stability and moisture resistance while minimizing equivalent series resistance.

Implementation Method 1

an insulating layer disposed to cover the first and second band portions on the first surface of the capacitor body and to cover portions of the first and second connection portions

Methodology Applied

Scientific EffectVibration absorption: Damping

Implementation Method 2

The dielectric layers have piezoelectric and electrostrictive properties. Thus, when a direct current (DC) or alternating current (AC) voltage is applied to an MLCC, a piezoelectric phenomenon may occur between internal electrodes, thereby causing the occurrence of vibrations.

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS9978523B1Multilayer capacitor and board having the multilayer capacitor mounted thereon

Publication Date: 2018.05.22 SAMSUNG ELECTRO MECHANICS CO LTD

AI summary

A multilayer capacitor includes a capacitor body including a dielectric layer and a plurality of first and second internal electrodes, the capacitor body having a first surface and a second surface opposing each other, the capacitor body having a third surface and a fourth surface connected to the first surface and the second surface and opposing each other, and first and second band portions extended from the first and second connection portions to portions of the first surface and the second surface of the capacitor body and portions of a fifth surface and a sixth surface of the capacitor body, respectively, an insulating layer covering the first and second band portions, and a first terminal electrode and a second terminal electrode covering the first and second external electrodes, and portions of the insulating layer disposed on the first surface of the capacitor body and spaced apart from each other.