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:
Dec. 19, 2000
Filed:
Jan. 26, 1999
Burkhard Speit, Mainz, DE;
Gerhard Westenberger, Mainz, DE;
Schott Glas, Mainz, DE;
Abstract
The glasses used for making rigid disk substrates have the following composition (based on the % by weight of the oxides): SiO.sub.2, 40 to 60; Al.sub.2 O.sub.3, 5 to 20; B.sub.2 O.sub.3, 0 to 5; Li.sub.2 O, 0 to 10; Na.sub.2 O, 0 to 12, with the proviso that Li.sub.2 O+Na.sub.2 O 5 to 12; K.sub.2 O, 0 to 5; MgO, 0 to 20; CaO, 0 to 6, with the proviso that MgO+CaO, 4 to 20,SrO+BaO, 0 to 10; Zr.sub.2 O, 0 to 5; TiO.sub.2, 0 to 5; CeO.sub.2, 0 to 1; La.sub.2 O.sub.3, 0 to 10; Fe.sub.2 O.sub.3, 0 to 10; Nb.sub.2 O.sub.5, 0 to 10; V.sub.2 O.sub.5, 0 to 15, with the proviso that TiO.sub.2 +ZrO.sub.2 +La.sub.2 O.sub.3 +Fe.sub.2 O.sub.3 +Nb.sub.2 O.sub.3 +V.sub.2 O.sub.5 .gtoreq.8, As.sub.2 O.sub.3 +Sb.sub.2 O.sub.3 +F, 0.1 to 1; or, SiO.sub.2, 10 to 30; Al.sub.2 O.sub.3, 0 to 5; B.sub.2 O.sub.3, 0 to 8; Li.sub.2 O, 0 to 8; Na.sub.2 O, 1 to 10, with the proviso that Li.sub.2 O+Na.sub.2 O, 5 to 10; K.sub.2 O, 0 to 3; MgO, 0 to 12; CaO, 0 to 15, with the proviso that MgO+CaO,10 to 15, SrO+BaO, 0 to 8; Zr.sub.2 O, 0 to 8; TiO.sub.2, 10 to 25; La.sub.2 O.sub.3, 0 to 10; Nb.sub.2 O.sub.5, 10 to 18; V.sub.2 O.sub.5, 0 to 20; CeO.sub.2, 0 to 1; As.sub.2 O.sub.3 +Sb.sub.2 O.sub.3 +F, 0.1 to 1. Both types or groups of glasses fulfill the following inequality formulae (1):