Optical glass

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PROBLEM TO BE SOLVED : To provide an optical glass having a low deformation temperature, a high refractive index, and a high transmittance and being suited for mold pressing. SOLUTION : Provided is an optical glass containing phosphorus, bismuth, and zinc in amounts in terms of oxides : 15-30 mol% P2O5, 5-35 mol% Bi2O3, and 40-75 mol% ZnO and further containing fluorine in an amount of 0.01-0.4 in terms of an F/O molar ratio. This glass may further contain aluminum in an amount of not larger than 10 mol% in the form of Al2O3, may further contain at least one alkali element R selected from among lithium, sodium and potassium, and used in an amount of not larger than 15 mol% in the form of R2O, and may further contain at least one element M selected from a rare earth element and gallium and used in an amount of not larger than 5 mol% in terms of an oxide (M2O3). In these cases, F in the form of ZnF2, AlF3, RF, or MF3is added so as to satisfy the above specified F/O molar ratio. COPYRIGHT : (C)2010, JPO&INPIT