| 摘要 |
PROBLEM TO BE SOLVED: To provide glass suitable for optical members or elements used in a semiconductor aligner and having a high refractive index nd while having viscosity capable of large molding.SOLUTION: There is provided glass containing, by mass% in terms of oxide, BOcomponent of 20% to 60%, LaOcomponent of 20% to 50%, GdOcomponent of 0% to 30%, YOcomponent of 0% to 30% and RO component of 1% to 45%, where R is one or more kinds selected from Zn, Mg, Sr, Ca, Ba) with total amount of the LaOcomponent, GdOcomponent and YOcomponent of 20% to 50%, a value of mass ratio of LaO/(LaO+GdO+YO+YbO) of 0.50 to 0.95 and a value of mass ratio of (LaO+GdO+YO+YbO)/(ZnO+MgO+SrO+CaO+BaO) of 1.50 to 5.00.SELECTED DRAWING: None |
