Patent · US Expired

Optical fluorophosphate glasses possessing positive anomalous partial dispersion and improved physico-chemical properties, and a process for their preparation

US4857487A · kind A · utility

8Cited by

6References

4Claims

0Family size

Assignee

Ernst Leitz Wetzlar, GmbH · DE

Inventors

Heinz Broemer · Wetzlar, DE
Werner Huber · Witzenhausen, DE
Norbert Meinert · Witzenhausen, DE

Key dates

Filing date	Nov 8, 1988
Grant date	Aug 15, 1989
Priority date	—
Expiry date	Nov 8, 2008

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10S501/902
WIPO fieldMaterials, metallurgy
WIPO sectorChemistry

Abstract

Optical fluorophosphate glasses based on Ba(PO.sub.3).sub.2, Al(PO.sub.3).sub.3, alkaline earth metal fluorides and AlF.sub.3 are described which have a refactive index n.sub.e between 1.47 and 1.50, an Abbe-value .nu..sub.e between 85 and 80 and a positive anomalous partial dispersion value .DELTA..nu..sub.e between +17 and +22. They comprise (in wt.-%) 0.5-3 Mg, 8-10 Ca, 12-20 Sr, 9-12 Ba, 7-9 Al, 5-9 P, 8-12 O and 35-38 F. Ti, Na, K and H may additionally be present. The improved physico-chemical parameters (expansion coefficient, glass transition temperature, density, Knoop-hardness) and the transmission characteristics are given, and a process for producing these optical glasses is described.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.