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:
Mar. 03, 1992
Filed:
Sep. 19, 1990
Yukihiro Kimura, Nagoya, JP;
Nobuhiko Miyawaki, Nagoya, JP;
Sumihito Tominaga, Nagoya, JP;
Rokuro Kanbe, Nagoya, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A multilayer ceramic wiring board including a ceramic board having a plurality of through-holes and formed by laminating three or more green sheets of a ceramic material and burning a laminate of the green sheets, and a plurality of conductors provided in the through-holes. Each of the conductors is formed of a ceramic material and a conductive material in combination. The ceramic board is composed of a pair of upper and lower layer portions each having at least an outermost surface layer and an inner layer portion disposed between the upper and lower portions. The conductors are composed of an outer conductor portion formed in the upper and lower layer portions and an inner conductor portion formed in the inner layer portion. The outer conductor portion has a content ratio of the ceramic material higher than that of the inner conductor portion. Accordingly, the generation of cracks in the outer conductor portion disposed at the upper and lower layer portions of the ceramic board can be prevented, and an electric resistance can be reduced.