Optical glass having high refractive index and low expansion coefficient

Abstract

Abstract PURPOSE:To obtain an optical glass having high refractive index and low expansion coefficient, and suitable as the core glass of optical fiber, by using ZnO together with one or more compounds selected from Y2O3, La2O3 and Gd2O3 and one or more compounds selected from TiO2, Nb2O5 and Ta2O3 as essential components within specific ranges. CONSTITUTION:The optical glass having a composition (wt%) of SiO2, 20-40; PbO, 40-65 (provided that SiO2+PbO<87.5); Al2O3, 0.5-10; ZnO, 2-15; Y2O3+ La2O3+Gd2O3, 0.5-12; TiO2+Nb2O3+Ta2O5, 0.5-7 (provided that Y2O3+ La2O3+Gd2O3+TiO2+Nb2O3+Ta2O5 is 5-15); B2O3, 0-6. The refractive index (nd) is 1.72-1.81, and the expansion coefficient of the glass is 40-65X10<-7>/ deg.C.

Inventors

• 👤 Hisao Hatta
• 👤 八田　比佐雄

Bibliographic Details