Multilayer Capacitor Built-in Substrate Noise Suppression

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Solution Overview

Problem

High-capacitance multilayer ceramic capacitors generate vibrations when voltage is applied, leading to acoustic noise due to their piezoelectric properties, which is exacerbated when mounted on substrates with burying layers, making it difficult to suppress noise effectively.

Innovation Solution

A multilayer capacitor built-in substrate design with a core substrate and a burying layer where the thickness of the burying layer is larger than the core substrate, and the height of the effective region is less than one-fourth of the burying layer thickness, significantly reducing acoustic noise by optimizing the structural dimensions and electrode connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high dielectric constant ceramic materials are used to increase capacitance, then capacitance is improved, but acoustic noise is generated due to piezoelectric distortion

Engineering Contradiction:

ImprovecapacitanceVSAvoidacoustic noise

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent applies this principle by using the piezoelectric distortion effect not as a harmful phenomenon to be eliminated, but as a mechanism to be utilized. The multilayer ceramic capacitor is designed to generate controlled mechanical vibrations through its piezoelectric properties, and these vibrations are then used to drive a piezoelectric speaker element, converting the harmful acoustic noise into a useful sound output function.

Inventive Principle:

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

Solution Approach 2:

The patent merges two previously separate functions into a single integrated device. The multilayer ceramic capacitor, which traditionally only stores electrical energy, is combined with piezoelectric speaker elements to create a hybrid component that simultaneously performs both capacitance storage and sound generation functions, eliminating the need for separate speaker components.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of manufacture

If multilayer ceramic capacitors are mounted on substrates with burying layers, then substrate integration is improved, but vibrations are propagated to substrates increasing acoustic noise

Engineering Contradiction:

Improvesubstrate integrationVSAvoidacoustic noise propagation

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an intermediary layer or structure between the multilayer ceramic capacitor and the substrate that serves as a vibration isolation medium. This intermediary element absorbs or dampens the mechanical vibrations generated by the capacitor's piezoelectric effect, preventing their propagation to the substrate and reducing acoustic noise while maintaining the electrical connection and substrate integration.

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

The design effectively reduces or prevents acoustic noise by minimizing substrate vibrations, as demonstrated by sound pressure level measurements, showing improved noise suppression compared to conventional designs.

Implementation Method 1

These high dielectric constant ceramic materials include piezoelectric and electrostrictive properties, and thus, in multilayer ceramic capacitors including dielectrics composed of the high dielectric constant ceramic materials, mechanical distortion will be produced when a voltage is applied.

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

Methodology Applied

Scientific EffectElectrostrictive effect: Electrostriction

Data Source

PatentUS10531565B2Multilayer capacitor built-in substrate

Publication Date: 2020.01.07 MURATA MFG CO LTD

AI summary

A multilayer capacitor built-in substrate includes a core substrate, a multilayer capacitor mounted on one principal surface of the core substrate, and a burying layer provided on the one principal surface of the core substrate to bury the multilayer capacitor. The multilayer capacitor includes a laminated body in which dielectric layers and internal electrode layers are laminated, and first and second external electrodes. The laminated body includes an effective region in which internal electrode layers respectively connected to the first external electrode and the second external electrode are laminated with a dielectric layer located therebetween, and a non-effective region surrounding the effective region. The core substrate includes, on the one principal surface, a first land electrode electrically connected to the first external electrode and a second land electrode electrically connected to the second external electrode.