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:
Apr. 17, 2001
Filed:
May. 08, 1998
Masuo Okada, Taihaku-ku, Sendai-shi, Miyagi, JP;
Takahiro Sawaguchi, Miyagi, JP;
Masatada Yodogawa, Tokyo, JP;
Dai Matsuoka, Arlington, MA (US);
Other;
Abstract
The PTC thermistor material of the invention comprises a matrix phase and electrically conductive phases substantially uniformly dispersed in the matrix phase, said conductive phases having a resistivity lower than that of the matrix phase, and has a resistivity changing sharply in the vicinity of the melting point of the conductive phases. The matrix phase is made up of any one of a polycrystalline ceramic material, a glass-polycrystalline ceramic composite material, a glass, a crystallized glass, and a polymer material, and the conductive phases are made up of a metal containing bismuth as a main component. It is thus possible to achieve a PTC thermistor material which can be controlled in terms of various properties such as the temperature at which PTCR property becomes available and the rate of resistivity change and so can be applied to circuit parts through which large currents pass in a normal operation state. Further, the PTC thermistor material can be easily manufactured with the stable PTCR property maintained. Furthermore, the PTC thermistor material can be operated with an increased rated current albeit being of small size, and has a high degree of shape freedom.