Laminated Ceramic Capacitor With Gradient Dielectric Thickness

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Solution Overview

Problem

Laminated ceramic capacitors face issues with insulation resistance deterioration and thermal shock resistance due to thin dielectric layers, which are exacerbated by high electrical field concentrations and mechanical strength limitations.

Innovation Solution

A laminated ceramic electronic component design featuring a cuboid-shaped element with internal electrode layers and a dielectric layer thickness that increases from the central portion to the side faces, alleviating electrical field concentration and improving reliability, while the thickness ratio of the dielectric and internal electrode layers is optimized to enhance thermal shock resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the dielectric layer is made thin to reduce component size, then the capacity increases and size decreases, but the insulation resistance deteriorates and reliability decreases due to increased electrical field intensity

Engineering Contradiction:

Improvecomponent sizeVSAvoidinsulation resistance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The dielectric layer thickness is made non-uniform, being thinner at the central portion and thicker at the end portions. This local variation in thickness allows the central region to maintain high capacitance while the end portions provide enhanced insulation resistance by reducing electrical field concentration, thus resolving the contradiction between small size and reliable insulation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The thickness parameter of the dielectric layer is changed from a uniform value to a gradient distribution where the thickness ratio d2/d1 ranges from 1.05 to 1.30. This parameter change optimizes the balance between capacitance (requiring thin layers) and insulation resistance (requiring thick layers at critical locations).

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the dielectric layer thickness is increased at the end portions to prevent electrical field concentration, then the insulation resistance improves, but the component size increases

Engineering Contradiction:

Improveinsulation resistanceVSAvoidcomponent size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

Instead of uniformly increasing the dielectric layer thickness throughout the component, the invention applies increased thickness only at the end portions where electrical field concentration occurs. The central portion maintains its thin thickness for high capacitance, thus improving insulation resistance without significantly increasing overall component size.

Inventive Principle:

Principle #3Local quality

3Reliability

If the dielectric layer becomes thin, then the capacity increases, but the thermal shock resistance deteriorates due to decreased mechanical strength

Engineering Contradiction:

ImprovecapacitanceVSAvoidthermal shock resistance

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The dielectric layer thickness is optimized locally: thin at the central portion for high capacitance and thicker at the end portions for enhanced mechanical strength and thermal shock resistance. The thickness ratio d2/d1 of 1.05 to 1.30 ensures that the end portions can withstand thermal stress while the central region maintains high electrical capacity.

Inventive Principle:

Principle #3Local quality

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 achieves improved reliability and thermal shock resistance for laminated ceramic capacitors with thin dielectric layers by distributing heat release and reducing thermal expansion coefficient differences, thereby preventing cracks and maintaining insulation resistance.

Implementation Method 1

the thickness of the dielectric layer becomes larger from the central portion towards the first side face and the second side face... the concentration of the electrical field is alleviated

Methodology Applied

Scientific EffectElectrical field distribution: Electric Field

Implementation Method 2

the heat release becomes lower at the part closer to the central region in the laminating direction... distributing heat release

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

the ratio of d2 to d1 (d2/d1) gradually gets larger from the outmost layer towards the central region in the laminating direction... enhancing thermal shock resistance

Methodology Applied

Scientific EffectThermal shock resistance: Thermal Shock

Data Source

PatentUS10090106B2Laminated ceramic electronic component

Publication Date: 2018.10.02 TDK CORP

AI summary

A laminated ceramic electronic component with a cuboid-shaped element main body having a first main face and a second main face elongating along the length direction and the width direction, a first side face and a second side face elongating along the length direction and the height direction, and a first end face and a second end face elongating along the width direction and the height direction; and a pair of internal electrode layers opposite to each other in the height direction inside the element main body with a dielectric layer interposed therebetween in such a manner that they are exposed at the first end face or the second end face, wherein the thickness of the dielectric layer becomes larger from central portion to the first side face and the second side face.