optical glass with negative teildispersion in a blue field, brechungsindices n amp; amp; darr; d amp; amp; darr; from 1.69 to 1.83 and pay v amp; amp; darr; d amp; amp; darr; from 29 to 38.5

摘要

it is a chemically stable, at relatively low schmelztemperaturen herstellbares glass with anomalous negative teildispersion pg, f, brechungsindices nd from 1.69 to 1.83 and payment of d of 29 to 38.5 is described. the glass contains (in wt.-% to product): $f1 with the proviso that the ratio of (sio2 + geo2 + b2o3) / (ta2o5 + zro2) 5, and the ratio of pbo / (sio2 + geo2 + b2o3) is smaller than 2, as well as usual lu00e4uterhilfsmittel.