| 摘要 |
<p>An optical glass characterized in that it exhibits a refractive index of from 1.695 to 1.705, a dispersive index of from 40.5 to 43.2, a density below 3.2 g/cm<3>, a weight loss as measured in the AO test of less than 0.15 mg/cm<2> and a transmittance at 400 nm in 10 mm thickness of at least 75% and it comprises, expressed in terms of weight percent on the oxide basis, from 16 to 21.5% CaO, from 6 to 15% La2O3, from 3.5 to less than 9% TiO2, from 5.5 to 12% Al2O3, from 3 to 11% Nb2O5, from 2 to 10% ZrO2, from 20.5 to 25% B2O3 and from 16 to 20% SiO2 is disclosed.
<??>The present glasses offer advantages over the prior art particularly for use in high correction ophthalmic lenses.</p> |
