Kabushiki Kaisha Ohara Kogaku Garasu Seizosho

Kabushiki Kaisha Ohara Kogaku

Fujio Komorita

Muneo Nakahara

Satoshi Inoue

Nobuhiro Nozawa

An optical glass of a B.sub.2 O.sub.3 --SiO.sub.2 --La.sub.2 O.sub.3 --Yb.sub.2 O.sub.3 system and additionally containing SnO.sub.2 is stable in spectral transmissivity, is scarcely liable to tinting and has high refractive and low dispersive characteristics.

Optical glass

An optical glass consisting basically of a B.sub.2 O.sub.3 -La.sub.2 O.sub.3 - ZrO.sub.2 -Nb.sub.2 O.sub.5 -PbO-BaO (and/or ZnO) system is free from a poisonous CdO or ThO.sub.2 component and has an excellent light transmission property in a transition region from an ultraviolet portion to a visible portion as compared with conventional optical glasses having the same optical properties.

An optical glass consisting essentially of a B.sub.2 O.sub.3 --La.sub.2 O.sub.3 --Gd.sub.2 O.sub.3 --WO.sub.3 --ZrO.sub.2 and/or Ta.sub.2 O.sub.5 system has high refractive and low dispersive characteristics with optical constants of 1.85-1.96 for Nd and 43-28 for .nu.d, is free of poisonous ThO.sub.2, CdO and BeO ingredients, and suitable for mass production.

An optical glass consisting basically of a B.sub.2 O.sub.3 -- SiO.sub.2 -- La.sub.2 O.sub.3 -- ZrO.sub.2 -- TiO.sub.2 -- ZnO -- BaO system can be produced at a lower melting temperature and in a shorter melting time than it has heretofore been possible by replacing Ta.sub.2 O.sub.5, Nb.sub.2 O.sub.5 and WO.sub.3 used in the conventional optical glasses with ZnO.

An optical glass consisting essentially of a B.sub.2 O.sub.3 -SiO.sub.2 -La.sub.2 O.sub.3 -Gd.sub.2 O.sub.3 -Y.sub.2 O.sub.3 system and additionally containing ZrO.sub.2 has high refractive and low dispersive characteristics and is free of a poisonous thorium oxide ingredient.

Growing community of inventors

Hachioji, Japan

Fujio Komorita