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:
Jan. 07, 1997
Filed:
Jun. 02, 1995
Naoyuki Goto, Sagamihara, JP;
Kabushiki Kaisya Ohara, , JP;
Abstract
A low expansion glass-ceramic which has a coefficient of thermal expansion (.alpha..times.10.sup.-7 /.degree.C.) within the range of from -5 to +5 within a temperature range of from -60.degree. C. to +160.degree. C., has a remarkably reduced variation of 10 ppm or below in relative length of .DELTA.1/1, has an excellent optical homogeneity owing to reduced melting temperature in the base glass, and has an improved transparency is obtained by restricting the ratio in weight of P.sub.2 O.sub.5 to SiO.sub.2 within the range of from 0.08 to 0.20, and adding Li.sub.2 O, MgO, ZnO, CaO and BaO of specific content ranges as essential ingredients in a base glass of a SiO.sub.2 -P.sub.2 O.sub.5 -Al.sub.2 O.sub.3 -Li.sub.2 O system containing TiO.sub.2 and ZrO.sub.2 as nucleating agents, and As.sub.2 O.sub.3 as an optional ingredient.