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. 23, 2013
Filed:
Dec. 24, 2009
Tsutomu Shibata, Owariasahi, JP;
Keita Nakagawa, Nagoya, JP;
Tsutomu Shibata, Owariasahi, JP;
Keita Nakagawa, Nagoya, JP;
NGK Spark Plug Co., Ltd., Nagoya, JP;
Abstract
Provided is a spark plug which allows a predetermined resistance to be imparted to a resistor with restraint of variation in resistance of the resistor and in turn, enables enhancement of yield. The spark plug includes a ceramic insulator having an axial hole extending in the direction of an axis CL, a center electrode, and a terminal electrode. A resistor is provided in the axial hole through sintering of a resistor composition which contains a conductive material such as carbon black, glass powder, and ceramic particles other than glass. As viewed on a section of the resistor taken along a direction orthogonal to the axis CL, 50% or more of sintered glass powder formed through sintering of the glass powder has a circularity of 0.8 or greater.