Optical glass and process for making precise-pressed optical elements therefrom as well as said optical elements

Abstract

The lead-free, preferably lithium-free, optical glass is useful in imaging, projection, telecommunications, optical communication and/or laser technology, particularly for making precise-pressed optical elements. It has a refractive index nd of 1.50 to 1.57, an Abbé number νd of 61 to 70. It also has a low transformation temperature of about or below 400° C., good production and processing properties and crystallization resistance. It has a composition, in percent by weight, based on oxide content of P2O5, 40 to 60; Al2O3, 1 to 20; B2O3, 0 to <5; Na2O, 0 to 30; K2O, 0 to 30; Li2O, 0 to <1; ΣM2O, >15 to 40; BaO, 1 to 20; ZnO, 1 to 20; SrO, 0 to 5; CaO, 0 to 5; MgO, 0 to 5; and ΣMO, 5 to 25. In addition, it may contain standard refining agents, although it is preferably free of arsenic and fluorine.

Dependencies are inferred from the claim text.