Optical colored glass, its use and sharp skirt optical filter

Die Erfindung betrifft ein optisches Farbglas der Zusammensetzung (in Gew.-% auf Oxidbasis) SiO2 30 - 75; K2O 5 - 35, B2O3 > 4 - 17, ZnO 5 - 37; F 0,01 - 10, CdO 0,1 - 1, S + Se + Te 0,1 - 1,5 sowie die Verwendung dieses Glases als Steilkantenfilter. Optical colored glass comprises (in wt.%) 30-75 silica, 5-35 potassium oxide, more than 4 to 17 boric oxide, 5-37 zinc oxide, 0.01-10 fluorine, 0.1-1 cadmium oxide, and 0.1-1.5 sulfur + selenium + tellurium. Preferred Features: The glass comprises (in wt.%) 30-75 silica (SiO2), 5-35 potassium oxide (K2O), more than 4 to 17 boric oxide (B2O3), 5-30 zinc oxide (ZnO), 0.01-10 fluorine (F), 0.1-1 cadmium oxide (CdO), and 0.1-1.5 sulfur + selenium + tellurium (S + Se +Te), preferably 40-65 SiO2, 15-29 K2O, 5-16 B2O3, 9-30 ZnO, 0.01-10 F, 0.1-1 CdO, and 0.1-1.1 S + Se +Te. The glass additionally contains (in wt.%) 0-20 sodium oxide (Na2O), 0-20 magnesium oxide (MgO), 0-20 calcium oxide (CaO), 0-20 CaO + MgO, 0-10 alumina (Al2O3), 0 to less than 10 strontium oxide (SrO), 0 to less than 10 barium oxide (BaO), 0-5 lanthanum oxide (La2O3), 0-5 niobium oxide (Nb2O5), 0-5 tantalum oxide (Ta2O5), 0-5 ceria (CeO2), 0-5 zirconia (ZrO2), and 0-10 phosphorus pentoxide (P2O5).