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:
Nov. 24, 1992
Filed:
Aug. 12, 1991
Applicant:
Inventors:
Akira Yamakawa, Itami, JP;
Tadashi Igarashi, Itami, JP;
Assignee:
Sumitomo Electric Industries, Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
428141 ; 428212 ; 428217 ; 428334 ; 428336 ; 428693 ; 428698 ; 428699 ; 428701 ; 360103 ; 360122 ;
Abstract
A ceramic substrate which comprises a ceramic base material having porosity of not more than 5% and surface roughness R.sub.max of not larger than 0.1 .mu.m, and an amorphous aluminum oxide film having thickness of 1 to 50 .mu.m formed on a surface of said ceramic base material, has high reliability and can be easily surface finished with high accuracy and can be used to form a thin film magnetic circuit.