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:
Jan. 29, 2002
Filed:
Sep. 11, 1997
Applicant:
Inventors:
Makoto Sugimoto, Nagoya, JP;
Yutaka Tanaka, Nagoya, JP;
Assignee:
NGK Spark Plug Co., Ltd., Nagoya, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C03C 2/702 ; C03C 2/704 ;
U.S. Cl.
CPC ...
C03C 2/702 ; C03C 2/704 ;
Abstract
In a spark plug in which a space between a center electrode at the top end side and a terminal electrode at a rear end side which are arranged to be opposite to each other in an axial hole of an insulator, the glass seal is effected at a temperature within the range of 500 to 1000° C. and under a condition where the concentration of oxygen is 4-12 vol %.