Dielectric Film Core-Shell Ceramic Particles Breakdown Strength

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Solution Overview

Problem

Dielectric films with high ceramic particle volume ratios face a trade-off between increased relative permittivity and breakdown field strength, as electric field energy concentration in ceramic particles does not effectively raise permittivity, while increasing electric field intensity in organic resin decreases breakdown field strength.

Innovation Solution

A dielectric film comprising ceramic particles with two or more crystalline phases of different axial ratios, arranged in a core-shell structure, is used to distribute electric field energy and maintain high breakdown field strength, allowing for increased relative permittivity without compromising breakdown voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If ceramic particles are contained at a relatively high volume ratio in the dielectric film, then relative permittivity is improved, but breakdown field strength decreases

Engineering Contradiction:
Improverelative permittivityVSAvoidbreakdown field strength
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent applies local quality by creating a core-shell structure where the ceramic particle has different properties in different regions. The core contains high-permittivity ceramic material while the shell contains organic resin with high breakdown strength. This allows the particle interior to contribute to permittivity while the shell protects against breakdown, resolving the contradiction between high permittivity and high breakdown field strength

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining ceramic particles with organic resin in a core-shell configuration. The ceramic core provides high relative permittivity while the organic resin shell provides high breakdown field strength. This composite structure allows the dielectric film to simultaneously achieve both high permittivity and high breakdown field strength, which cannot be achieved with single-material particles

Inventive Principle:
Principle #40Composite materials

2Volume of moving object

If the film thickness is reduced to downsize the film capacitor, then packaging density is improved, but breakdown field strength requirement increases

Engineering Contradiction:
Improvefilm capacitor sizeVSAvoidbreakdown field strength
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The core-shell composite particle structure enables the use of thinner dielectric films by providing inherently high breakdown field strength at the particle level. The organic resin shell acts as a protective barrier that prevents electrical breakdown, allowing the overall film thickness to be reduced while maintaining or even improving breakdown performance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters of the particles by creating a core-shell structure with different material compositions. This allows the dielectric film to achieve higher breakdown field strength in thinner configurations, enabling downsizing of the film capacitor while meeting breakdown strength requirements

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 dielectric film achieves higher permittivity and breakdown field strength, enabling smaller, high-capacity film capacitors with improved packaging density and rectifying capabilities in electronic devices.

Implementation Method 1

concentration of electric field energy (εr × E^2/2) resulting from an applied electric field

Methodology Applied
Scientific EffectDielectric permittivity: Dielectric Permittivity

Implementation Method 2

the metallic membrane located around the defective area is vaporized for release under energy of short-circuiting

Methodology Applied
Scientific EffectVaporization: Evaporation

Data Source

PatentEP3029694B1Dielectric film, film capacitor and electric device
Publication Date: 2022.01.26 KYOCERA CORP
  • EP3029694B1 patent drawingFigure 1
  • EP3029694B1 patent drawingFigure 2
  • EP3029694B1 patent drawingFigure 3

AI summary

There are provided a dielectric film, a film capacitor and an electric device capable of achieving an increase in relative permittivity without causing a decrease in breakdown field strength. A dielectric film includes an organic resin (5) and ceramic particles (3) contained in the organic resin (5). The ceramic particles (3) each have a crystal lattice defined by three axes composed of axis a, axis b, and axis c, and including two or more crystalline phases (3a, 3b) of different axial ratios c/a. Owing to each crystal phase (3a, 3b) having different extents of dielectric polarization originating from the differences in shapes (sizes) of the crystal lattices, the ceramic particles (3) each have regions with different permittivities, achieving an increase in relative permittivity without causing a decrease in breakdown field strength.