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:
Jul. 24, 2012
Filed:
May. 10, 2011
Naoaki Abe, Nagaokakyo, JP;
Hayato Katsu, Nagaokakyo, JP;
Masato Goto, Nagaokakyo, JP;
Atsushi Kishimoto, Nagaokakyo, JP;
Akinori Nakayama, Nagaokakyo, JP;
Naoaki Abe, Nagaokakyo, JP;
Hayato Katsu, Nagaokakyo, JP;
Masato Goto, Nagaokakyo, JP;
Atsushi Kishimoto, Nagaokakyo, JP;
Akinori Nakayama, Nagaokakyo, JP;
Murata Manufacturing Co., Ltd., Nagaokakyo-Shi, Kyoto-fu, JP;
Abstract
A semiconductor ceramic includes a BaTiO-based composition, as a main component, having a perovskite structure represented by general formula ABO. Part of the A site Ba is replaced with an alkali metal element, Bi, Ca, Sr, and a rare-earth element. When the molar amounts of Ca and Sr are x and y, respectively, and the total number of moles of the elements constituting the A site is 1 mole, 0.05≦x≦0.20, 0.02≦y≦0.12, and 2x+5y≦0.7. A PTC thermistor includes a component body formed of the semiconductor ceramic. Even when an alkali metal element and Bi are present, there is provided a lead-free semiconductor ceramic with high reliability in which the surface discoloration is not caused and the degradation of resistance over time can be suppressed even after the application of an electric current for a long time.