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:
Feb. 09, 1982
Filed:
Jul. 30, 1980
Werner Sack, Mainz, DE;
Otto Lindig, Mainz, DE;
Schott Glaswerk, Mainz, DE;
Abstract
A fusion glass of the series SiO.sub.2 --Al.sub.2 O.sub.3 --Na.sub.2 O--PbO--Fe.sub.3 O.sub.4 consists essentially of 43.0-46.2% by weight of SiO.sub.2 ; 1.0-2.0% by weight of Al.sub.2 O.sub.3 ; 6.2-16.0% by weight of Na.sub.2 O; 33.0-46.1% by weight of PbO; 2.0-4.5% by weight of Fe.sub.3 O.sub.4 ; and a maximum of 0.2% by weight of Sb.sub.2 O.sub.3, all calculated as percent by weight of oxide. These heat-absorbing fusion glasses having a low softening point can be used especially for the hermetic encapsulation of electrotechnical components, especially of conductor contacts operated magnetically as well as nonmagnetically, having coefficients of thermal expansion in the temperature range of 20.degree.-300.degree. C. of about 8.4-12.2.times.10.sup.-6 /.degree.C. and maximum heat absorption at about 1 to 1.5 .mu.m. These glasses have softening temperatures (ST) of about 537.degree. to 601.degree. C., processing temperatures (PT) of about 763.degree. to 879.degree. C., and a lower tendency toward varporization during the fusion process. The fusion stresses between the metallic conductor and the glass, existing after the fusion process and occurring upon rapid cooling in air and after a 5.degree. C./min cooling step, are characterized by a maximum tensile stress corresponding to an optical path difference of .ltoreq.400 nm/cm, at a specific birefringence of about (2.7.+-.0.1).times.10.sup.-6 mm.sup.2 /N.