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:
Aug. 30, 1977
Filed:
Jul. 14, 1975
Seiichi Yamada, Machida, JA;
Kyohei Murakawa, Yokohama, JA;
Fujitsu Limited, Kawasaki, JA;
Abstract
An improved alumina substrate comprising alumina and magnesium oxide has a surface finish of no more than 0.05 .mu.m CLA and a density of at least 3.90 g/cm.sup.3 in an as-fired condition and is composed of alumina grains which are sufficiently grown to have straight grain boundaries and flat surfaces to form a surface of the substrate. The improved substrate is produced by firing a green sheet having a high content of raw material powder and a density of more than 2.60 g/cm.sup.3 at a temperature of 1525.degree. to 1650.degree. C. The green sheet with high density is formed by the process of aggregating an organic agent and a high purity alumina powder by dry milling and casting the resultant slip.