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. 14, 2002
Filed:
Feb. 22, 1999
Naoyuki Goto, Sagamihara, JP;
Kousuke Nakajima, Samukawa-machi, JP;
Kabushiki Kaisha Ohara, Kanagawa-ken, JP;
Abstract
A glass-ceramic substrate for a magnetic information recording medium contains, as a main crystal phase or phases, one or more crystal phases selected from the group consisting of &bgr;-quartz (&bgr;-SiO ), &bgr;-quartz solid solution (&bgr;-SiO solid solution), &bgr;-spodumene (&bgr;-Li O.Al O .4SiO ), &bgr;-spodumene solid solution (&bgr;-Li O.Al O .4SiO solid solution), &bgr;-eucryptite (&bgr;-Li O.Al O .2SiO , a part of Li O being capable of being substituted by MgO and/or ZnO) and &bgr;-eucryptite solid solution (&bgr;-Li O.Al O .2SiO solid solution, a part of Li O being capable of being substituted by MgO and/or ZnO). Alternatively, the glass-ceramic contains, as a main crystal phase or phases, gahnite (ZnAl O ) and/or gahnite solid solution (ZnAl O solid solution). The glass-ceramic substrate has a high heat resisting property and a super flat surface capable of achieving a high recording density according to the perpendicular magnetic recording.