Patent ID: 8431499

Claim:
A fluorophosphate glass comprising: the following cations: P 5+ in an amount of 20 to 45 cationic %; Al 3+ in an amount of 15 to 35 cationic %; Ba 2+ in an amount of 20 to 50 cationic %; and B 3+ in an amount of 0 to 5 cationic %; and the following anions: F − in an amount of 20 to 50 anionic %; and O 2− in an amount of 50 to 80 anionic %; wherein: a molar ratio of O 2− /P 5+ is larger than or equal to 3.50; a molar ratio of Al 3+ /P 5+ is less than or equal to 1; Abrasion FA is less than or equal to 600, or Knoop hardness number is greater than or equal to 300 MPa; Abbe number (νd) of the glass is greater than or equal to 66; a refractive index (nd) of the glass satisfies an expression (1): nd≧ 2.0614−0.0071 ×νd (1); and the fluorophosphate glass does not contain Cu in an amount by which Cu serves as a coloring agent.