IP Library › Granted Patent US 6,975,502
Granted Patent B2
US 6,975,502 · App. 11/094,604 · Granted Dec 13, 2005

Multilayer ceramic capacitor

Assignee: TDK Corporation
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Quick Facts
Patent No.
US 6,975,502
App. No.
11/094,604
Granted
Dec 13, 2005
Kind
B2
Abstract

A multilayer ceramic capacitor including an internal electrode layer, an internal dielectric layer having a thickness of less than 2 μm, and an external dielectric layer is provided, wherein the internal dielectric layer and external dielectric layer contain a plurality of dielectric particles, and when assuming that an average particle diameter of the entire dielectric particles in the internal dielectric layer is D50a (unit: μm), an average particle diameter of the entire dielectric particles existing at a position being away at least by 5 μm from the outermost internal electrode layer in the thickness direction is D50b (unit: μm), a ratio (D50a/D50b) of the D50a and D50b is y (no unit), standard deviation of a particle size distribution of the entire dielectric particles in the internal dielectric layer is σ (no unit), and a ratio that dielectric particles (coarse particles) having an average particle diameter of 2.25 times of the D50a exist in the entire dielectric particles is p (unit: %), the y and x satisfy a relationship of y<−0.75x+2.015 and y>−0.75x+1.740, the σ satisfies σ<0.091 and the p satisfies p<2.85%; by which a TC bias characteristic can be expected to be improved while maintaining various electric characteristics, particularly a sufficient permittivity, even when the internal dielectric layer is made thin.

Claims (11)

1. A multilayer ceramic capacitor comprising an internal electrode layer, an internal dielectric layer having a thickness of less than 2 μm, and an external dielectric layer wherein:

said internal dielectric layer and the external dielectric layer are formed by including a plurality of dielectric particles;

an average particle diameter of the entire dielectric particles in said internal dielectric layer is D50a (unit: μm), and

an average particle diameter of the entire dielectric particles existing at a position being away at least by 5 μm from the outermost internal electrode layer in the thickness direction in said external dielectric layer is D50b (unit: μm),

the ratio (D50a/D50b) of said D50a and said D50b is assumed to be y (no unit); and

a thickness of said internal dielectric layer is x (unit: μm),

standard deviation of a particle size distribution of the entire dielectric particles in said internal dielectric layers is σ (no unit), and

a ratio that dielectric particles (coarse particles) having an average particle diameter of 2.25 times of said D50a exist in the entire dielectric particles of said internal dielectric layer is p (unit: %)

said y and x satisfy a relationship of y<−0.75x+2.015 and y>−0.75x+1.740,

said σ satisfies σ<0.091, and

said p satisfies p<2.85%.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 31, 2005
From: MUROSAWA, TAKAKO; MIYAUCHI, MARI; NOGUCHI, KAZUNORI; SATO, AKIRA
To: TDK CORPORATION
Reel/Frame 016442/0125 →
Priority Claims (1)
JP 2004-103145 · Mar 31, 2004 · national
Continuity (1)
Related Publication 20050219795A1 · Oct 6, 2005