Patents Represented by Law Firm Foley & Lardner, Schwartz, Jeffery, Schwaab, Mack, Blumehthal & Evans
  • Patent number: 4857487
    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.
    Type: Grant
    Filed: November 8, 1988
    Date of Patent: August 15, 1989
    Assignee: Ernst Leitz Wetzlar GmbH
    Inventors: Heinz Broemer, Werner Huber, Norbert Meinert