Patent ID: 6066273
Filing Date: 2000-05-23
Classification: C03C,G02B

Abstract:
An axial refractive index distributed lens obtained by forming in a glass material, a refractive index distribution in the direction of the optical axis thereof by an ion exchange method using silver,said glass material comprising a glass composition having the following composition:10<Na.sub.2 O.ltoreq.25 mol %8<Al.sub.2 O.sub.3 .ltoreq.25 mol %0.ltoreq.MgO.ltoreq.18 mol %0.ltoreq.ZnO.ltoreq.18 mol %7.ltoreq.B.sub.2 O.sub.3 .ltoreq.18 mol %35.ltoreq.SiO.sub.2 .ltoreq.55 mol %0.ltoreq.La.sub.2 O.sub.3 .ltoreq.5 mol %0.ltoreq.BaO.ltoreq.5 mol %0.ltoreq.Ta.sub.2 O.sub.5 .ltoreq.3 mol %0.ltoreq.ZrO.sub.2 .ltoreq.3 mol %provided that2.5.ltoreq.MgO+ZnO.ltoreq.18 mol %.