Patent ID: 7994082

Claim:
A precision press molding preform, characterized by being comprised of an optical glass the components of which are: P 2 O 5 : 15 to 70 molar percent, Nb 2 O 5 : 1 to 30 molar percent TiO 2 : 0 to 9.984 molar percent (excluding 0 molar percent), Bi 2 O 3 : 6 to 30 molar percent (excluding 6 molar percent) B 2 O 3 : 0 to 30 molar percent, WO 3 : equal to or more than 2 molar percent, BaO: equal to or less than 10 molar percent, Li 2 O: 2 to 30 molar percent, SiO 2 : 0 to 2 molar percent, ZnO: 0 to 12 molar percent, which has a refractive index (nd) more than 1.80, a liquid-phase temperature equal to or lower than 910° C. and an Abbé number (vd) of less than or equal to 32, and where the molar ratio of (TiO 2 content/Bi 2 O 3 content) is less than 2.917 and the molar ratio TiO 2 Nb 2 O 5 is <0.3328.