The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 19, 2002
Filed:
Jul. 23, 1999
Yoshihiko Ishida, Nagoya, JP;
NGK Insulators, Ltd., Nagoya, JP;
Abstract
An inorganic-metal composite body exhibiting PTC behavior at a trip point temperature ranging from 40° C.-300° C., including an electrically insulating inorganic matrix having a room temperature resistivity of at least 1×10 &OHgr;·cm, and electrically conductive particles uniformly dispersed in the matrix and forming a three-dimensional conductive network extending from a first surface of said body to an opposed second surface thereof, wherein the composite body has a room temperature resistivity of no more than 10 &OHgr;·cm and a high temperature resistivity of at least 100 &OHgr;·cm. Preferably, the electrically conductive particles are made of a Bi-based alloy containing at least 50 wt % Bi, and have an average diameter, &phgr; , of 5-50 &mgr;m and a 3&sgr; particle size distribution of 0.5 &phgr; −2.0 &phgr; . Also disclosed is an inorganic PTC device including an intermediate electrode layer to insure adhesion of outer termination electrodes to the PTC composite body, and a method of forming the composite body, which method effectively deals with the volatility of the electrically conductive particles.