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:
Oct. 15, 1985
Filed:
Jun. 24, 1983
Taiyo Yuden Co., Ltd., Tokyo, JP;
Abstract
Ceramic materials suitable for use in varistors, enabling the same to function not only as such but also as capacitors. The ceramic materials comprise a major proportion of SrTiO.sub.3, the balance being: (1) at least one of Nb.sub.2 O.sub.5, Ta.sub.2 O.sub.5, WO.sub.3, La.sub.2 O.sub.3, CeO.sub.2, Nd.sub.2 O.sub.3, Y.sub.2 O.sub.3, Pr.sub.6 O.sub.11, Sm.sub.2 O.sub.3, Eu.sub.2 O.sub.3, and Dy.sub.2 O.sub.3, for making the materials semiconductive; (2) Na.sub.2 O, for making surge-proof the varistors made from the ceramic materials and for improving their nonlinearity coefficients; and (3) Al.sub.2 O.sub.3, for improving the temperature dependences of the varistor voltages, as well as nonlinearity coefficients, of the varistors. Optionally the ceramic materials may further contain one or more of Ag.sub.2 O, CuO, MnO.sub.2, and SiO.sub.2, for still higher nonlinearity coefficients. Containing Al.sub.2 O.sub.3 in proportions ranging from 0.01 to 1.50 mole parts with respect to 100 mole parts of SrTiO.sub.3, the ceramic compositions make possible the provision of varistors having varistor voltages that hardly change in a temperature range as wide as, for example, from -40.degree. to +120.degree. C.