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. 29, 2002
Filed:
Sep. 07, 2000
Applicant:
Inventor:
Tomonori Niwa, Aichi, JP;
Assignee:
NGK Spark Plug Co., Ltd., Aichi, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B32B 9/04 ;
U.S. Cl.
CPC ...
B32B 9/04 ;
Abstract
A sintered silicon nitride member formed predominantly of silicon nitride, wherein at least a surface of the sintered member has a lightness VS of 3.0 to 9.0 and/or a chroma CS of not greater than 3.0. The sintered member facilitates identification of defects such as pore and/or foreign matter of different color formed at the surface and is capable of enhancing inspection accuracy. Also disclosed is a sintered silicon nitride member in the form of a ceramic ball having such a lightness on its surface.