Optical and ophthalmic glass with refractive indices greater than or equal to 1.56, Abbe numbers greater than or equal to 40 and densities less than or equal to 2.70 g/cm.sup.3

US4719186A · kind A · utility

Assignee

• Schott Glaswerke · DE

Inventors

• Karl Mennemann · Taunusstein, DE
• Georg Gliemeroth · Eltville am Rhein, DE
• Ludwig Ross · Klein-Winternheim, DE
• Burkhard Speit · Mainz, DE
• Volkmar Geiler · Ingelheim am Rhein, DE
• Hans-Georg Krolla · Mainz, DE
• Lothar Meckel

Key dates

• Filing date: Apr 16, 1986
• Grant date: Jan 12, 1988
• Expiry date: Apr 16, 2006

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S501/903
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

An optical and ophthalmic glass with high refractive index, high Abbe number and low density, which is distinguished by good chemical stability, good crystallization behavior and capability of chemical hardening, comprises (in % by weight): ______________________________________ SiO.sub.2 50-63 B.sub.2 O.sub.3 4-8 Al.sub.2 O.sub.3 1-2 Li.sub.2 O 4-8 Na.sub.2 O 4-8 K.sub.2 O 3-7 sum of M.sub.2 O 11-20 (M = Li, Na, K) MgO 0.5-2 CaO 2-5 sum of MO 0-3 (M = Mg, Ca) TiO.sub.2 8-12.5 ZrO.sub.2 1-3 F.sup.- 0-1 As.sub.2 O.sub.3 0.05-0.15 (optional refining agent) Sb.sub.2 O.sub.3 0.0-0.2 (optional refining agent) ______________________________________