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:
Mar. 23, 1999
Filed:
Jul. 24, 1996
Manabu Nishizawa, Yokohama, JP;
Yasumasa Nakao, Yokohama, JP;
Asahi Glass Company Ltd., Tokyo, JP;
Abstract
An alkali-free glass consisting essentially of from 60 to 74 mol % of SiO.sub.2, from 10 to 16 mol % of Al.sub.2 O.sub.3, from 10 to 12 mol % of B.sub.2 O.sub.3, the molar ratio of Al.sub.2 O.sub.3 /B.sub.2 O.sub.3 being from 1.0 to 1.5, from 0 to 5 mol % of MgO, from 0 to 5 mol % of CaO, from 0 to 12 mol % of SrO, from 0 to 12 mol % of BaO, and from 6 to 12 mol % of SrO+BaO, which contains substantially no alkali metal oxide and has a strain point exceeding 650.degree. C. and an average thermal expansion coefficient of at most 40.times.10.sup.-7 /.degree.C. within a range of from 50.degree. to 300.degree. C., and of which the weight loss per unit area after immersion at 25.degree. C. for 20 minutes in a liquid prepared by mixing a 40 wt % ammonium fluoride aqueous solution and a 50 wt % hydrofluoric acid aqueous solution in a volume ratio of 9:1, is less than 0.60 mg/cm.sup.2, the weight loss per unit area after immersion at 95.degree. C. for 20 hours in 0.1N HCl, is less than 0.20 mg/cm.sup.2, and the liquidus temperature is at most a temperature at which the viscosity is 10.sup.4 poise.