LIGHTWEIGHT OPTICAL GLASS HAVING HIGH REFRACTIVE INDEX

Title:

LIGHTWEIGHT OPTICAL GLASS HAVING HIGH REFRACTIVE INDEX

Document Type and Number:

Japanese Patent JPS62275038

Kind Code:

A

Abstract:

PURPOSE: To obtain the titled glass wherein specific gravity, refractive index and Abbe number are respectively regulated to specified ranges and it is suitable for spectacles by incorporating the composition of a specified range.

CONSTITUTION: The titled glass is obtained which has the composition of by wt% 5W36SiO2, 6W35B2O≥3 however 23W42 (SiO2+B2O3), 0W8 MgO, 0W27 CaO, 0W4 BaO, 0W11 ZnO however 10W32 (MgO+CaO+BaO+ZnO), 16W32 TiO2, 17W27 La2O3, 0W2 Y2O3, 0W2 Yb2O3, 0W10 Al2O3, 0W4 Li2O, 0W4 Na2O, 0W4 K2O however 0W4 (Li2O+Na2O+K2O), 0W7 ZrO2, 0W13 Nb2O5 and 0W0.2 Nd2O3, and is regulated to 1.80W1.85 refractive index (nd), 29W32 Abbe number (Vd) and 3.0W3.7 specific gravity. Glass having 1.80W1.84 refractive index (nd), 31W32 (excluding 32) Abbe number (Vd) and 3.0W3.7 specific gravity is obtained from the composition of by wt% 16W25 TiO2, 4W13 Nb2O5, 9W25 CaO and 18W27 La2O3 among these compositions for glass and therefore is especially preferable as glass for spectacles.

Inventors:

KIDO KAZUHIRO

Application Number:

JP11143686A

Publication Date:

November 30, 1987

Filing Date:

May 15, 1986

Export Citation:

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Assignee:

NIKON CORP

International Classes:

C03C3/068; (IPC1-7): C03C3/068

Attorney, Agent or Firm:

Takao Watanabe

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