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:
May. 23, 1989
Filed:
Oct. 08, 1987
Applicant:
Inventors:
Takashi Kijima, Yokohama, JP;
Jyun Matsui, Yokohama, JP;
Takaaki Sera, Yokohama, JP;
Takayuki Kobayashi, Yokohama, JP;
Shunji Takakusa, Tokyo, JP;
Hiroshi Ogata, Fujisawa, JP;
Assignee:
Asahi Glass Company Ltd., Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
B32B / ;
U.S. Cl.
CPC ...
428141 ; 65 31 ; 156646 ; 156663 ; 427129 ; 428426 ; 428694 ; 428900 ;
Abstract
A glass substrate for a magnetic disc having a finely and isotropically roughened surface, wherein the maximum height R.sub.max of the surface roughness is substantially not higher than 700 .ANG. at a standard length of 250 .mu.m and substantially not less than 50 .ANG. at a standard length of 50 .mu.m.