Precision press formable glass used in production of optical part comprises oxides of boron, yttrium, silicon, lithium, calcium, zinc and gadolinium

摘要

Precision press formable glass comprises oxides of boron, yttrium, silicon, lithium, calcium, zinc and 0-7 gadolinium and/or zirconium, sodium, potassium, strontium, barium, tantalum, aluminum, ytterbium, niobium, titanium, antimony and arsenic. The glass has a refractive index nd of 1.67-1.71, an Abbe number nu d of 50-55, a liquidus temperature of less than 950 deg C and a glass transition temperature Tg of 545 deg C or less. Precision press formable glass comprises (in wt.%): 26-39 boron oxide, 4-11 yttrium oxide, 3-17 silicon oxide, 3-7 lithium oxide, 2-17 calcium oxide, 5-18 zinc oxide and 0-7 gadolinium oxide and/or 0-7 zirconium oxide. The gadolinium oxide and zirconium oxide are contained so that the total amount of them is 0.5-12. The glass also contains 0-3 sodium oxide, 0-3 potassium oxide, 0-3 strontium oxide, 0-7 barium oxide, 0-4 tantalum oxide, 0-3 aluminum oxide, 0-3 ytterbium oxide, 0-4 niobium oxide, 0-2 titanium oxide, 0-2 antimony oxide and 0-2 arsenic oxide. The glass has a refractive index nd of 1.67-1.71, an Abbe number nud of 50-55, a liquidus temperature of less than 950 deg C and a glass transition temperature Tg of 545 deg C or less. An Independent claim is also included for the production of an optical part comprising heating the precision press formable glass of the above composition; and press forming the softened glass.