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:
Aug. 23, 2016
Filed:
Feb. 21, 2014
Ngk Spark Plug Co., Ltd., Nagoya-shi, Aichi, JP;
Kengo Fujimura, Aichi-ken, JP;
Toshimasa Saji, Aichi-ken, JP;
Hirokazu Kurono, Aichi-ken, JP;
Toshitaka Honda, Aichi-ken, JP;
NGK Spark Plug Co., Ltd., Nagoya-shi, JP;
Abstract
An insulator used in a spark plug having improved strength and dielectric strength performance. The insulator comprises a sintered compact whose main constituent is alumina. In the sintered compact, a content ratio of a rare earth element (R. E.) and a group 2 element (2A) satisfies 0.1≦R. E./2A ≦1.4, and the content ratio of the R. E. and barium oxide (BaO) satisfies 0.2≦BaO/R. E.≦0.8. At least one virtual rectangular frame of 7.5 μm×50 μm surrounding crystals containing the rare earth element lies within a region of 630 μm×480 μm in any cross section of the sintered compact.