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:
Jun. 04, 2002
Filed:
Sep. 22, 1999
Shoichi Kishimoto, Osaka, JP;
Akihiro Koyama, Osaka, JP;
Junji Kurachi, Osaka, JP;
Nobuyuki Yamamoto, Osaka, JP;
Nippon Sheet Glass Co., Ltd., Osaka, JP;
Abstract
A glass composition having a high Young's modulus and a low density is disclosed which can be mass-produced by a continuous process and easily made to have high surface smoothness. Also disclosed are a substrate including the glass composition and reduced in bending and resonance even upon high-speed rotation, a recording medium usable at a lower flying height, and an information recording device having a higher recording capacity and a shorter access time. The glass composition includes, in terms of mol %, 40 to 55% silicon dioxide (SiO ), 0.5 to 6% aluminum oxide (Al O ), 2 to 20% lithium oxide (Li O), 0 to 10% sodium monoxide ((Na O), 2 to 30% R O (R O=Li O+Na O), 5 to 25% magnesium oxide (MgO), 0 to 25% calcium oxide (CaO), 0 to 10% strontium oxide (SrO), 10 to 40% RO (RO=MgO+CaO+SrO), 0 to 10% titanium dioxide (TiO ), and 0 to 5% zirconium oxide (ZrO ).