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. 16, 2007
Filed:
Jul. 30, 2002
Kazuho Tatematsu, Aichi, JP;
Masahiro Konishi, Aichi, JP;
Takeshi Yamaguchi, Aichi, JP;
NGK Spark Plug CC., Ltd., Aichi, JP;
Abstract
A ceramic heaterincludes a silicon nitride ceramic substrateand a resistance-heating memberembedded in the silicon nitride ceramic substrate. The silicon nitride ceramic substratecontains oxygen derived from a sintering aid at an average concentration of 0.4–3.2% by weight in a surface layer portion extending from the surface thereof to a depth of 1 mm. The ceramic heatercan be manufactured by firing through hot pressing. A firing jig for use in a firing process has an SiC—C composite layer which is formed therein along the surface of cavities thereof while having a predetermined depth as measured from the cavity surface.