Dielectric film, film capacitor, and electric device

Patent metadata

Field	Value
Publication number	US-9679699-B2
Application number	US-201414906341-A
Country	US
Kind code	B2
Filing date	Jul 30, 2014
Priority date	Jul 30, 2013
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

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 and ceramic particles contained in the organic resin. The ceramic particles 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 of different axial ratios c/a. Owing to each crystal phase having different extents of dielectric polarization originating from the differences in shapes (sizes) of the crystal lattices, the ceramic particles each have regions with different permittivities, achieving an increase in relative permittivity without causing a decrease in breakdown field strength.

First claim

The invention claimed is:

1. A dielectric film, comprising:
an organic resin; and
ceramic particles contained in the organic resin,
the ceramic particles each having a crystal lattice defined by three axes composed of axis a, axis b, and axis c, and including two or more crystalline phases of different axial ratios c/a, and an electrostatic energy density of the dielectric film being greater than or equal to 6220800.

2. The dielectric film according to claim 1 ,
wherein the ceramic particles each have the crystal lattice defined by the three axes composed of axis a, axis b, and axis c, and include only two crystalline phases of different axial ratios c/a.

3. The dielectric film according to claim 2 ,
wherein the ceramic particles each have a core-shell structure composed of a core portion and a shell portion positioned around the core portion, and the core portion is constituted by one of the two crystalline phases, and the shell portion is constituted by the other one of the two crystalline phases.

4. The dielectric film according to claim 3 ,
wherein the crystalline phase constituting the shell portion is smaller in axial ratio c/a than the crystalline phase constituting the core portion.

5. The dielectric film according to claim 4 ,
wherein the ceramic particles are a ceramic particle having a perovskite structure.

6. The dielectric film according to claim 3 ,
wherein the ceramic particles each contain magnesium, and the shell portion is higher in magnesium content concentration than the core portion.

7. A film capacitor, comprising:
the dielectric film according to claim 1 ; and
an electrode layer disposed on the dielectric film.

8. An electric device, comprising:
an electric circuit including a conductor; and
the film capacitor according to claim 7 connected to the conductor.

9. The dielectric film according to claim 4 ,
wherein a difference of axial ratios c/a between the crystalline phase constituting the shell portion and the crystalline phase constituting the core portion is 0.008 or more.

Assignees

• Kyocera Corp

Inventors

• Kamigaki Kousei

Classifications

• H01G4/18 Primary

  of synthetic material, e.g. derivatives of cellulose (H01G4/16 takes precedence) · CPC title

• C08K3/00

  Use of inorganic substances as compounding ingredients · CPC title

• C08L101/00

  Compositions of unspecified macromolecular compounds · CPC title

• H01G4/33

  Thin- or thick-film capacitors {(thin- or thick-film circuits; capacitors without a potential-jump or surface barrier specially adapted for integrated circuits, details thereof, multistep manufacturing processes therefor)} · CPC title

• C04B35/4682

  based on BaTiO3 perovskite phase · CPC title