Patent Number: 8,713,970

Title: Method for producing fluorophosphate glass, glass material for press molding and optical element

Abstract: In order to produce a fluorophosphate glass including P.sup.5+ at a small content on the composition thereof, the composition is adjusted so as to provide well-balanced chemical durability and thermal stability. In the production of a fluorophosphate glass in which O.sup.2-/P.sup.5+>3.7, Al.sup.3+ content is in a predetermined amount or more and p.sup.5+ content is in a predetermined amount or less, a glass raw material is prepared by using an AlF.sub.3 in which the content of Al.sub.2O.sub.3 is limited to the range from 1 to 5% by mass, and the raw material is melted to produce the fluorophosphate glass.

Inventors: Ikenishi; Mikio (Akishina, JP)

Assignee: Hoya Corporation

International Classification: C03C 3/247 (20060101)

Expiration Date: 5/06/12018