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:
Apr. 08, 1997
Filed:
May. 23, 1995
Mitsubishi Kasei Corporation, Tokyo, JP;
Abstract
Disclosed herein is a substrate for a magnetic disc comprising a glass substrate having fine protrusions on its surface, the protrusions having a height of 50 to 1000 .ANG., a width of 0.01 to 1 .mu.m, a density of 10 to 1000 per 100 .mu.m.sup.2 and an area ratio of 0.1 to 50%, and a ratio of peak height on a mean line (R.sub.p) to maximum height (R.sub.max) with respect to surface roughness of the substrate being at least 60%. Further, a process for preparing the substrate and a magnetic disc having the substrate are disclosed. Because the substrate according to the present invention has appropriate protrusions on its surface, a friction force and an adsorbing force between a head and a magnetic disc can be reduced, leading to the improvement of the CSS and the anti-head stick properties. In addition, the S/N ratio is not affected because the fine concave portions formed on the surface of the substrate are shallow.