| 摘要 |
<p>The present invention relates to glasses of high refractive index having the following composition of oxides, expressed in percentages by weight: SiO2 27 - 36, B2O3 0 - 9, Li2O 1 - 5, Na2O 1 - 7, K2O 0 - 7, CaO 0 - 7, BaO 4 - 13, ZnO 0 - 8, La2O3 4 - 15, PbO 4 - 27, TiO2 7 - 18, ZrO2 0 - 9, Nb2O5 0 - 8 with: Li2O+Na2O+K2O 6 - 15, SiO2+TiO2+ZrO2 42 - 55, PbO+TiO2+ZrO2+Nb2O5 29 - 40; their use for the production of segments for multifocal corrective lenses; and multifocal corrective lenses incorporating at least one such segment in their structure.</p> |
