Patent ID: 8546282

Claim:
A glass for a light guide fiber that is used in a core of a fiber of a light guide, wherein the glass has a refractive index nd between 1.56 and 1.74 and has a composition described hereunder: (A) SiO 2 : 20 to 55 wt %, (B11) B 2 O 3 : 0 to 2.0 wt %, (B2) does not contain P 2 O 5 and GeO 2 , (C1) (BaO+SrO+La 2 O 3 +Lu 2 O 3 +Ta 2 O 5 +Gd 2 O 3 +WO 3 ): 39 to 46 wt %, (D1) ZnO: 4 to 16 wt %, (E) does not contain Al 2 O 3 , (F) does not contain ZrO 2 , (G) does not contain PbO and As 2 O 3 , (H1) (Na 2 O+K 2 O): 4 to 10 wt %, (I) Sb 2 O 3 : 0 to 0.050 wt %, and (J1) (Na 2 SO 4 +K 2 SO 4 ): 0.32 to 0.78 wt %.