Capacitor Mounting Structure for Noise Reduction

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Solution Overview

Problem

Existing capacitor element mounting techniques fail to effectively reduce noise in electronic devices without increasing the size of the device, particularly when laminated ceramic capacitors are mounted on a single surface of the wiring board, due to limitations in circuitry design and structural constraints.

Innovation Solution

A capacitor element mounting structure and method where multiple rectangular capacitor elements are mounted on a wiring board in a specific configuration, with each element having a multilayer body of dielectric and internal electrode layers, and are electrically connected in series or parallel via a conductive pattern, allowing for perpendicular orientation of their long sides and strategic placement of outer electrodes to cancel out vibrations, thereby reducing noise without increasing the device's size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If laminated ceramic capacitors are mounted on front and rear surfaces of wiring board in plane symmetry, then noise is reduced through vibration cancellation, but device thickness and size increase

Engineering Contradiction:

ImprovenoiseVSAvoiddevice size

Core Design Contradiction:

Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The invention transitions from three-dimensional mounting (front and rear surfaces of the wiring board) to two-dimensional mounting (single surface), thereby reducing device thickness and size while maintaining the noise reduction function through alternative spatial arrangement of capacitor elements on the same surface

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If laminated ceramic capacitors are mounted on front and rear surfaces of wiring board, then noise is reduced through vibration cancellation, but circuit board thickness increases

Engineering Contradiction:

ImprovenoiseVSAvoidcircuit board thickness

Core Design Contradiction:

Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The invention relocates capacitor elements from the thickness dimension (front and rear surfaces) to the planar dimension (single surface), arranging them in specific geometric patterns that enable vibration cancellation without increasing board thickness

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Object-affected harmful factors

If technique requiring ripple voltages to be applied respectively to pair of laminated ceramic capacitors is used, then noise is reduced through opposite phase vibrations, but mounting layout freedom is restricted and extra space is required

Engineering Contradiction:

ImprovenoiseVSAvoidmounting layout freedom

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The invention employs asymmetric mounting layouts of capacitor elements on the wiring board surface, where elements are positioned at different locations and orientations rather than requiring symmetric placement, thereby achieving vibration cancellation without restricting circuitry design freedom or requiring extra space

Inventive Principle:

Principle #4Asymmetry

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 significantly reduces noise while preventing an increase in the size of the electronic device by effectively canceling out vibrations, allowing for more design freedom and efficient use of space on the circuit board.

Implementation Method 1

Such a high-permittivity ceramic material is piezoelectric and electrostrictive, and thus, applying a voltage in a laminated ceramic capacitor that includes a dielectric material configured of a high-permittivity ceramic material produces mechanical distortion.

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

Methodology Applied

Scientific EffectElectrostriction: Electrostriction

Implementation Method 3

mounting a pair of laminated ceramic capacitors having the same specifications in plane symmetry in corresponding positions on the front and rear surfaces of a wiring board so that vibrations transmitted from one of the laminated ceramic capacitors to the wiring board cancel out vibrations transmitted from the other laminated ceramic capacitor to the wiring board

Methodology Applied

Scientific EffectVibration cancellation through interference: Interference

Data Source

PatentUS9277647B2Capacitor element mounting structure and capacitor element mounting method

Publication Date: 2016.03.01 MURATA MFG CO LTD

AI summary

A circuit board includes a wiring board on which is mounted first and second laminated ceramic capacitors near or adjacent to each other, arranged along a direction parallel or substantially parallel to a main surface of the wiring board, and electrically connected in series or in parallel via a conductive pattern provided on the wiring board. One width direction side surface of the first laminated ceramic capacitor and one length direction end surface of the second laminated ceramic capacitor oppose each other perpendicularly or approximately perpendicularly.